diff --git a/nodejs/public/javascripts/safechat.js b/nodejs/public/javascripts/safechat.js
index f1bde7a..db17ee3 100644
--- a/nodejs/public/javascripts/safechat.js
+++ b/nodejs/public/javascripts/safechat.js
@@ -41,9 +41,15 @@ function SafeChat() {
 
   /// Create UID from a name by appending an E-Mail
   function uid(name) {
-    return name+' <'+name+'@'+hostname+'>'
+    return name+' <'+mail(name)+'>'
   }
 
+  function mail(name) {
+    var hostname = window.location.hostname!='localhost'?window.location.hostname:'safechat.ch'
+    return name+'@'+hostname
+  }
+  
+  //==============================================================================
   /// @class Crypto cryptographic functions
   /** @param view is of class SafeChat.View */
   function Crypto(controller) {
@@ -51,42 +57,23 @@ function SafeChat() {
     /// cache client's key from local strorage
     var k = null
 
-    /// detect hosstname, default to safechat.ch
-    var hostname = window.location.hostname!='localhost'?window.location.hostname:'safechat.ch'
-    
+    /// detect hostname, default to safechat.ch
     /// get user key
     /** @internal key ist cached in k
        @return key */
-    function key() {
-      if (k) return k
-      if (typeof localStorage.key == 'undefined') return null
-      return k = openpgp.key.readArmored(localStorage.key)
+    this.key = function() {
+      if (k) return k // cached key
+      if (typeof localStorage.privkey === 'undefined') return null
+      return k = openpgp.key.readArmored(localStorage.privkey)
     }
 
     /// get own user name
     /** get user name as user id of first public key */
-    function user() {
+    this.user = function() {
       if (k || key()) return k.pub.keys[0].getUserIds()[0]
       return null
     }
 
-    /// create New User
-    function createuser(user, email, pwd) {
-      controller.notice("generating keys")
-      openpgp.generateKey({
-        numBits: 4096,
-        userIds: [{name: user, email: email}],
-        passphrase: pwd
-      }).then(function(keyPair) {
-        controller.success("keys generated")
-        localStorage.key = keyPair.privateKeyArmored
-        k = keyPair.key
-      }).catch(function(e) {
-        console.log(e)
-        controller.fatal("generating key pairs failed")
-      })
-    }
-
     /// open private key with password
     /** @return @c true if password matches */
     function password(pwd) {
@@ -116,8 +103,15 @@ function SafeChat() {
       return true
     }
 
+    //------------------------------------------------------------------------------
+    if (openpgp.initWorker("openpgp.worker.min.js"))
+      console.log("asynchronous openpgp enabled")
+    else
+      console.log("asynchronous openpgp failed")
+    
   }
 
+  //==============================================================================
   /// database that stores in indexed db
   function DataBase() {
 
@@ -126,6 +120,7 @@ function SafeChat() {
     
   }
 
+  //==============================================================================
   /// manage local copy of users
   function Users() {
     
@@ -142,6 +137,7 @@ function SafeChat() {
     
   }
 
+  //------------------------------------------------------------------------------
   /// manage local copy of messages
   function Messages() {
     
@@ -152,6 +148,7 @@ function SafeChat() {
     
   }
 
+  //==============================================================================
   /// @class Communication client socket communication
   /** @param view is of class SafeChat.View */
   function Communication(controller) {
@@ -163,9 +160,13 @@ function SafeChat() {
       socket.broadcast.emit(signal, data)
     }
 
-    function emit(signal, data) {
+    function emit(signal, data, next) {
       console.log("<-snd "+signal)
-      socket.emit(signal, data)
+      socket.emit(signal, data, next)
+    }
+
+    this.lookup = function(usr, next) {
+      emit('user', usr, next)
     }
 
     socket
@@ -183,6 +184,7 @@ function SafeChat() {
     
   }
 
+  //==============================================================================
   /// @class View provides the glue to the GUI in the index.ejs file
   /** View provides the following callbacks:
      - status updates:
@@ -299,7 +301,7 @@ function SafeChat() {
         @param msg (optional) the success message text */
     function show(id, msg) {
       console.log("state: "+id)
-      if (msg) success(msg) else $("#status").hide()
+      if (msg) success(msg); else $("#status").hide();
       $("#main").children(":not(#"+id+")").hide()
       $("#main #"+id).show()
       $("#main #"+id+" form input:first-child").focus()
@@ -327,21 +329,15 @@ function SafeChat() {
     }
 
     function checkFeature(id, query) {
-      if (query) $('#'+id+':before')
-        .css('color', 'green')
-        .css('content', '&#x2714;')
-      else $('#'+id+':before')
-        .css('color', 'red')
-        .css('content', '&#x2718;')
       if (query) $('#'+id)
         .css('color', 'green')
-        .css('text-decoration', 'line-through')
+        .prepend('<span>&#x2714;</span>')
       else $('#'+id)
         .css('color', 'red')
-        .css('text-decoration', 'none')
+        .prepend('<span>&#x2718;</span>')
     }
 
-    function checkFeatures() {
+    this.checkFeatures = function() {
       $('ul.features').css('list-style-type', 'none')
       checkFeature("localstorage", Storage)
       checkFeature("indexeddb", window.indexedDB)
@@ -350,6 +346,54 @@ function SafeChat() {
       checkFeature("filereader", window.FileReader)
     }
 
+    /// @name create new user
+    /// @{
+    
+    this.newuser = function() {
+      show('newuser')
+    }
+
+    var user = null
+    var pwd = false
+
+    function invalid(usr) {
+      return !user || !user.exists && user.name.length<3
+    }
+    
+    this.available = function(usr) {
+      user = usr
+      console.log("props:", invalid(user) || !pwd)
+      $("#createuser").prop(":disabled", invalid(user) || !pwd)
+      if (user.length==0)
+        notice("please chose a user name")
+      else if (user.length<3)
+        notice("please chose a longer user name")
+      else if (user.exists)
+        notice("user name is already in use")
+      else if (!pwd)
+        notice("please chose a password")
+      else
+        success("user is ready to be created")
+    }
+    
+    this.passwords = function(pwd1, pwd2) {
+      pwd = pwd1==pwd2 && pwd1.length>5
+      console.log("props:", invalid(user) || !pwd)
+      $("#createuser").prop(":disabled", invalid(user) || !pwd)
+      if (pwd1.length==0)
+        notice('please chose a password')
+      else if (pwd1.length<6)
+        notice('please chose a longer password')
+      else if (pwd1 != pwd2)
+        notice("passwords don't match")
+      else if (invalid(user))
+        notice("please chose a user name")
+      else
+        success("user is ready to be created")
+    }
+
+    /// @}
+
     function DataTransfer() {
       
       var reboottimer = null
@@ -405,10 +449,11 @@ function SafeChat() {
 
   }
 
+  //==============================================================================
   /// @class Controller defines the programm flow
   function Controller(view) {
     
-    var db = new Database()
+    var db = new DataBase()
     var crypto = new Crypto(this)
     var communication = new Communication(this)
     var users = new Users()
@@ -461,6 +506,33 @@ function SafeChat() {
 
     // @}
 
+    /// @name signals from view
+    /// @{
+
+    /// @name new user registration
+    /// @{
+
+    this.lookup = function(usr) {
+      if (usr.length > 2) communication.lookup(uid(usr), function(res) {
+        view.available(res)
+      })
+    }
+    
+    this.checkpasswords = view.passwords
+
+    this.createuser = function(name, pwd) {
+      crypto.createuser(name, name+'@'+hostname, pwd).then(function() {
+        if (!crypto.password(pwd))
+          fatal("private key decryption failed")
+        else
+          chat()
+      })
+    }
+    
+    /// @}
+
+    /// @}
+
     function initBrowser() {
       window.indexedDB = window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB
       window.IDBTransaction = window.IDBTransaction || window.webkitIDBTransaction || window.msIDBTransaction
@@ -469,242 +541,248 @@ function SafeChat() {
       return window.indexedDB && window.crypto.getRandomValues && Storage
     }
 
-    function register() {
+    var newuser = view.newuser
+
+    function chat() {
+    }
+
+    function password() {
       
     }
 
     function login() {
-      if (!crypto.key()) register()
-      else password()
+      if (!crypto.key()) newuser(); else password();
     }
 
-    function run() {
+    this.run = function() {
       login()
     }
 
-    function start() {
-      view.reboot = run
+    this.start = function() {
+      view.reboot = this.run
       var compatible = initBrowser()
       view.checkFeatures()
       if (!compatible)
         view.fatal("your browser is not supported")
       else
-        run()
+        this.run()
     }
-
+    
   }
 
   //==============================================================================
-
-  //------------------------------------------------------------------------------
   return new Controller(new View())
 
 }
-  
-  var filecontent = new Array() ///< temporary storage for attachments
-  var reboottimer = null
-
-  function connectionstatus() {
-    if (socket.connected) connected() else disconnected()
-  }
-
-  /// Configure local groups
-  /** … */
-  function groups() {
-  }
 
-  /// Check if password is set and matches the repeated password
-  /** Checks if both passwords are identical and valid and gives
-     feedback to the user.
+//==============================================================================
+//------------------------------------------------------------------------------
+  
+var filecontent = new Array() ///< temporary storage for attachments
+var reboottimer = null
 
-     Called when user edits the password fields.
+function connectionstatus() {
+  if (socket.connected) connected(); else disconnected();
+}
 
-     Sets @ref username and checks @ref password - if both are well
-     defined, enables the submit button.
+/// Configure local groups
+/** … */
+function groups() {
+}
 
-     @param pwd The password.
-     @param pwd2 The repeated password. */
-  function checkpwd(pwd, pwd2) {
-    $("#register").submit(function(event) {
-      return false
-    })
-    if (pwd==pwd2) password=pwd
-    else password=null
-    if (!password||password.length<1) password=null
-    $("#createuser").prop("disabled", !(username && password))
-    if (password) {
-      if (username) success("user is ready to be created")
+/// Check if password is set and matches the repeated password
+/** Checks if both passwords are identical and valid and gives
+   feedback to the user.
+
+   Called when user edits the password fields.
+
+   Sets @ref username and checks @ref password - if both are well
+   defined, enables the submit button.
+
+   @param pwd The password.
+   @param pwd2 The repeated password. */
+function checkpwd(pwd, pwd2) {
+  $("#register").submit(function(event) {
+    return false
+  })
+  if (pwd==pwd2) password=pwd
+  else password=null
+  if (!password||password.length<1) password=null
+  $("#createuser").prop("disabled", !(username && password))
+  if (password) {
+    if (username) success("user is ready to be created")
       else notice("password matches, please chose a valid user name")
-    } else {
-      if (username) notice("passwords don't match")
+  } else {
+    if (username) notice("passwords don't match")
       else if ($('#user').val()) notice("user name is already in use")
-      else notice("please chose a user name")
-      
-    }
+    else notice("please chose a user name")
+    
   }
+}
 
-  /// Checks if the receiver of a message exists on server.
-  /** Calls checknewuser.php on server and enables the message submit
-     button if the receiver of the message exists on the server. */
-  function checkpartner(user) {
-    $("#chat").submit(function(event) {
-      return false
-    })
-    emit("user", uid(user))
-  }
+/// Checks if the receiver of a message exists on server.
+/** Calls checknewuser.php on server and enables the message submit
+   button if the receiver of the message exists on the server. */
+function checkpartner(user) {
+  $("#chat").submit(function(event) {
+    return false
+  })
+  emit("user", uid(user))
+}
 
-  /// Create Local Public-/Private-Key Pair
-  /** Called if user has not yet his keys, just generates a new key pair. */
-  function createkeypair(user, pwd) {
-    notice("generating keys")
-    openpgp.generateKey({
-      numBits: 4096,
-      userIds: [{name: user, email: user+'@'+hostname}],
-      passphrase: pwd
-    }).then(function(keyPair) {
-      success("keys generated")
-      localStorage.pubkey = keyPair.publicKeyArmored
-      localStorage.privkey = keyPair.privateKeyArmored
-      login()
-    }).catch(function(e) {
-      console.log(e)
-      error("generating key pairs failed")
-    })
-  }
+/// Create Local Public-/Private-Key Pair
+/** Called if user has not yet his keys, just generates a new key pair. */
+function createkeypair(user, pwd) {
+  notice("generating keys")
+  openpgp.generateKey({
+    numBits: 4096,
+    userIds: [{name: user, email: user+'@'+hostname}],
+    passphrase: pwd
+  }).then(function(keyPair) {
+    success("keys generated")
+    localStorage.pubkey = keyPair.publicKeyArmored
+    localStorage.privkey = keyPair.privateKeyArmored
+    login()
+  }).catch(function(e) {
+    console.log(e)
+    error("generating key pairs failed")
+  })
+}
 
-  /// Get Own Public Key
-  /** @return public key object */
-  function publicKey() {
-    if (typeof localStorage.pubkey == 'undefined') {
-      if (typeof localStorage.pubKey == 'undefined') {
-        return null
-      } else {
-        localStorage.pubkey = localStorage.pubKey
-        localStorage.removeItem(pubKey)
-      }
+/// Get Own Public Key
+/** @return public key object */
+function publicKey() {
+  if (typeof localStorage.pubkey == 'undefined') {
+    if (typeof localStorage.pubKey == 'undefined') {
+      return null
+    } else {
+      localStorage.pubkey = localStorage.pubKey
+      localStorage.removeItem(pubKey)
     }
-    return openpgp.key.readArmored(localStorage.pubkey)
   }
+  return openpgp.key.readArmored(localStorage.pubkey)
+}
 
-  /// Get Own Private Key
-  /** @return private key object */
-  function privateKey() {
-    if (typeof localStorage.privkey == 'undefined') {
-      if (typeof localStorage.privKey == 'undefined') {
-        return null
-      } else {
-        localStorage.privkey = localStorage.privKey
-        localStorage.removeItem(privKey)
-      }
+/// Get Own Private Key
+/** @return private key object */
+function privateKey() {
+  if (typeof localStorage.privkey == 'undefined') {
+    if (typeof localStorage.privKey == 'undefined') {
+      return null
+    } else {
+      localStorage.privkey = localStorage.privKey
+      localStorage.removeItem(privKey)
     }
-    return openpgp.key.readArmored(localStorage.privkey)
   }
+  return openpgp.key.readArmored(localStorage.privkey)
+}
 
-  /// Get Own User Name
-  /** Get user name as user id of first public key */
-  function userid() {
-    if (!publicKey() ||
-        publicKey().keys.length < 1 ||
-        publicKey().keys[0].getUserIds().length < 1) return null
-    return publicKey().keys[0].getUserIds()[0]
-  }
+/// Get Own User Name
+/** Get user name as user id of first public key */
+function userid() {
+  if (!publicKey() ||
+      publicKey().keys.length < 1 ||
+      publicKey().keys[0].getUserIds().length < 1) return null
+  return publicKey().keys[0].getUserIds()[0]
+}
 
-  /// Clear Message Text And Attachments
-  /** Does not remove the receiver's name */
-  function clearmessage() {
-    $("#message").prop(":disabled", true)
-    filecontent = new Array()
-    $('#preview').empty()
-    $("#msg").val("")
-    $("#message").prop(":disabled", false)
-  }
+/// Clear Message Text And Attachments
+/** Does not remove the receiver's name */
+function clearmessage() {
+  $("#message").prop(":disabled", true)
+  filecontent = new Array()
+  $('#preview').empty()
+  $("#msg").val("")
+  $("#message").prop(":disabled", false)
+}
 
-  function guessfilename(mimetype, user, date) {
-    if (!user) user = userid()
+function guessfilename(mimetype, user, date) {
+  if (!user) user = userid()
     if (!date) date = new Date()
-    var ext = mimetype.replace(/.*\/(x-)?/i, "")
-    return pad(date.getFullYear())+pad(date.getMonth()+1)+pad(date.getDate())
-          +"-"+ext+"-"+user+"@"+hostname+'.'+ext
-  }
+      var ext = mimetype.replace(/.*\/(x-)?/i, "")
+  return pad(date.getFullYear())+pad(date.getMonth()+1)+pad(date.getDate())
+        +"-"+ext+"-"+user+"@"+hostname+'.'+ext
+}
 
-  /// Display Image Attachments
-  function attachments(files, id, from, date) {
-    if (files) files.forEach(function(file) {
-      console.log(file)
-      if (!file.name) file.name = guessfilename(file.type, from, date)
+/// Display Image Attachments
+function attachments(files, id, from, date) {
+  if (files) files.forEach(function(file) {
+    console.log(file)
+    if (!file.name) file.name = guessfilename(file.type, from, date)
       var a = document.createElement('a')
-      a.href = file.content
-      a.download = file.name
-      a.target = '_blank'
-      if (file.type.match('^image/')) {
-        var img = document.createElement('img')
-        img.title = file.name
-        img.src = file.content
-        a.appendChild(img)
-      } else if (file.type.match('^video/')) {
-        var video = document.createElement('video')
-        video.controls = true
-        video.title = file.name
-        video.src = file.content
-        a.appendChild(video)
-      } else {
-        var img = document.createElement('img')
-        img.title = file.name
-        img.src = "images/Document_sans_PICOL-PIctorial-COmmunication-Language.svg"
-        a.appendChild(img)
-      }
-      $(id).append(a)            
-    })
-  }
+    a.href = file.content
+    a.download = file.name
+    a.target = '_blank'
+    if (file.type.match('^image/')) {
+      var img = document.createElement('img')
+      img.title = file.name
+      img.src = file.content
+      a.appendChild(img)
+    } else if (file.type.match('^video/')) {
+      var video = document.createElement('video')
+      video.controls = true
+      video.title = file.name
+      video.src = file.content
+      a.appendChild(video)
+    } else {
+      var img = document.createElement('img')
+      img.title = file.name
+      img.src = "images/Document_sans_PICOL-PIctorial-COmmunication-Language.svg"
+      a.appendChild(img)
+    }
+    $(id).append(a)            
+  })
+}
 
-  var recorder
+var recorder
 
-  function done() {
-    if (recorder) {
-      recorder.stop()
-      recorder.recording(function(data) {
-        previewfile(data, "video/webm")
-        abort()
-      })
-    }
+function done() {
+  if (recorder) {
+    recorder.stop()
+    recorder.recording(function(data) {
+      previewfile(data, "video/webm")
+      abort()
+    })
   }
+}
 
-  function abort() {
-    if (recorder) {
-      $("#videorecorder").hide()
-      recorder.release()
-      delete recorder recorder = null
-    }
+function abort() {
+  if (recorder) {
+    $("#videorecorder").hide()
+    recorder.release()
+    delete recorder
+    recorder = null
   }
+}
 
-  /// Record Video from builtin camera
-  function recordvideo() {
-    try {
-      abort()
-      $("#videorecorder").show()
-      recorder = new MediaStreamRecorder({
-        video: {
-          width: {ideal: 180},
-          height: {ideal: 160}
-        },
-        audio: true
-      })
-      recorder.on("ready", function() {
-        $("#videorecorder video").attr("src", recorder.preview())
-        $("#videorecorder video").css("width", 180)
-        $("#videorecorder video").css("height", 160)
-        $("#videorecorder video").attr("width", 180)
-        $("#videorecorder video").attr("height", 160)
-        recorder.start()
-      })
-    } catch (e) {
-      console.log(e)
-      error("cannot access camera", true)
-    }
+/// Record Video from builtin camera
+function recordvideo() {
+  try {
+    abort()
+    $("#videorecorder").show()
+    recorder = new MediaStreamRecorder({
+      video: {
+        width: {ideal: 180},
+        height: {ideal: 160}
+      },
+      audio: true
+    })
+    recorder.on("ready", function() {
+      $("#videorecorder video").attr("src", recorder.preview())
+      $("#videorecorder video").css("width", 180)
+      $("#videorecorder video").css("height", 160)
+      $("#videorecorder video").attr("width", 180)
+      $("#videorecorder video").attr("height", 160)
+      recorder.start()
+    })
+  } catch (e) {
+    console.log(e)
+    error("cannot access camera", true)
   }
+}
 
-  function previewfile(content, type, name) {
-    if (!name) name = guessfilename(type)
+function previewfile(content, type, name) {
+  if (!name) name = guessfilename(type)
     if (type.match('^image/')) {
       var img = document.createElement("img")
       img.onload = function() { // resize image to maximum 400px
@@ -748,334 +826,341 @@ function SafeChat() {
       img.title = name+"\n"+size(content.length)
       $("#preview").append(img)
     }
-  }
+}
 
-  /// Upload Attachment
-  /** Prepares attachment to be sent in a message. If the attachment is
-     an image, it resizes the image to 400px on the lager side.
-
-     By now, only images are supported.
-
-     Stores data in global variable @ref filecontent. */
-  function fileupload(evt) {
-    if (!window.FileReader)
-      return error("your browser does not support file upload", true)
-    for (var i=0, f; f=evt.target.files[i]; ++i) {
-      var file = f
-      var reader = new FileReader()
-      reader.onload = function(evt) {
-        if (evt.target.error) return error("error reading file", true)
+/// Upload Attachment
+/** Prepares attachment to be sent in a message. If the attachment is
+   an image, it resizes the image to 400px on the lager side.
+
+   By now, only images are supported.
+
+   Stores data in global variable @ref filecontent. */
+function fileupload(evt) {
+  if (!window.FileReader)
+    return error("your browser does not support file upload", true)
+  for (var i=0, f; f=evt.target.files[i]; ++i) {
+    var file = f
+    var reader = new FileReader()
+    reader.onload = function(evt) {
+      if (evt.target.error) return error("error reading file", true)
         if (evt.target.readyState==0) return notice("waiting for data …")
-        if (evt.target.readyState==1) return notice("loading data …")
-        previewfile(evt.target.result, file.type, file.name)
-      }
-      reader.readAsDataURL(file)
+          if (evt.target.readyState==1) return notice("loading data …")
+            previewfile(evt.target.result, file.type, file.name)
     }
+    reader.readAsDataURL(file)
   }
+}
 
-  /// Sets Receiver's Name
-  /** Called when clicked on a receiver's name. Sets focus to the
-     message text field.
+/// Sets Receiver's Name
+/** Called when clicked on a receiver's name. Sets focus to the
+   message text field.
 
-     @param name The receiver's name. */
-  function setreceiver(name) {
-    $("#recv").val(name)
-    checkpartner(name)
-    $("#msg").focus()
-  }
+   @param name The receiver's name. */
+function setreceiver(name) {
+  $("#recv").val(name)
+  checkpartner(name)
+  $("#msg").focus()
+}
 
-  var userMap = null
-  function users(userlist) {
-    console.log("rcv-> users")
-    userMap = new Array()
-    $("#allusers").empty()
-    userlist.forEach(function(usr) {
-      userMap[usr.name] = usr.pubkey
-      $("#allusers").append('<option value="'+htmlenc(usr.name)+'">')
-      $("#allusers").hide()
-      console.log("   user: "+usr.name)
-    })
-    localStorage.userMap = JSON.stringify(userMap)
-  }
+var userMap = null
+function users(userlist) {
+  console.log("rcv-> users")
+  userMap = new Array()
+  $("#allusers").empty()
+  userlist.forEach(function(usr) {
+    userMap[usr.name] = usr.pubkey
+    $("#allusers").append('<option value="'+htmlenc(usr.name)+'">')
+    $("#allusers").hide()
+    console.log("   user: "+usr.name)
+  })
+  localStorage.userMap = JSON.stringify(userMap)
+}
 
-  function user(usr) {
-    if (usr.exists) console.log("rcv-> user("+usr.name+")")
+function user(usr) {
+  if (usr.exists) console.log("rcv-> user("+usr.name+")")
     else console.log("rcv-> user("+usr.name+"): name is available")
-    if ($("#newuser").is(":visible") && usr.name==uid($('#user').val())) {
-      // same username as in the create user form
-      $("#createuser").prop("disabled", usr.exists) // todo: check password
-      if (!usr.exists) {
-        username = usr.name
-        success("user name "+usr.name+" is available")
-      } else {
-        username = null
-        error("user name "+usr.name+" is in use", true)
-      }
+  if ($("#newuser").is(":visible") && usr.name==uid($('#user').val())) {
+    // same username as in the create user form
+    $("#createuser").prop("disabled", usr.exists) // todo: check password
+    if (!usr.exists) {
+      username = usr.name
+      success("user name "+usr.name+" is available")
+    } else {
+      username = null
+      error("user name "+usr.name+" is in use", true)
     }
-    if ($("#chat").is(":visible") && usr.name==uid($("#recv").val())) { // same username as in receiver
-      $('#send').prop("disabled", !usr.exists)
-      $("label[for=send] img").css("opacity", usr.exists?"1.0":"0.4")
-      $("label[for=send] img").css("filter", usr.exists?"alpha(opacity=100)":"alpha(opacity=40)")
-      if (usr.exists) success("recipient exists")
+  }
+  if ($("#chat").is(":visible") && usr.name==uid($("#recv").val())) { // same username as in receiver
+    $('#send').prop("disabled", !usr.exists)
+    $("label[for=send] img").css("opacity", usr.exists?"1.0":"0.4")
+    $("label[for=send] img").css("filter", usr.exists?"alpha(opacity=100)":"alpha(opacity=40)")
+    if (usr.exists) success("recipient exists")
       else error("unknown recipient", true)
-    }
-    if (userMap == null) {
-      if (localStorage.userMap) {
-        userMap = JSON.parse(localStorage.userMap)
-      } else {
-        userMap = new Array()
-      }
-    }
-    if (usr.exists && usr.pubkey && userMap[usr.name] != usr.pubkey) {
-      userMap[usr.name] = usr.pubkey
-      $("#allusers").append('option value="'+htmlenc(usr.name)+'"')
-      localStorage.userMap = JSON.stringify(userMap)
+  }
+  if (userMap == null) {
+    if (localStorage.userMap) {
+      userMap = JSON.parse(localStorage.userMap)
+    } else {
+      userMap = new Array()
     }
   }
-
-  function queryuser(usr) {
-    console.log("query user: "+uid(usr))
-    socket.emit("user", uid(usr))
+  if (usr.exists && usr.pubkey && userMap[usr.name] != usr.pubkey) {
+    userMap[usr.name] = usr.pubkey
+    $("#allusers").append('option value="'+htmlenc(usr.name)+'"')
+    localStorage.userMap = JSON.stringify(userMap)
   }
+}
+
+function queryuser(usr) {
+  console.log("query user: "+uid(usr))
+  socket.emit("user", uid(usr))
+}
 
-  /// Get a user's public key.
-  /** The first time, gets it from the server, later from the cache. */
-  function getPublicKey(user) {
-    var deferredObject = $.Deferred()
-    if (userMap && userMap[user]) deferredObject.resolve(userMap[user])
+/// Get a user's public key.
+/** The first time, gets it from the server, later from the cache. */
+function getPublicKey(user) {
+  var deferredObject = $.Deferred()
+  if (userMap && userMap[user]) deferredObject.resolve(userMap[user])
     else deferredObject.reject("unknown user")
-    return deferredObject.promise()
-  }
+  return deferredObject.promise()
+}
 
-  /// Received a list of messages from server
-  function messages(msgs) {
-    console.log("rcv-> messages("+msgs.length+")")
-    if (!password || !privateKey())
-      return setTimeout(function() {emit("messages")}, 1000) // try again later
-    status("allmessages")
-    notice("load messages, please wait …")
-    msgs.forEach(function(msg) {message(msg, true)})
-    status("chat")
-  }
+/// Received a list of messages from server
+function messages(msgs) {
+  console.log("rcv-> messages("+msgs.length+")")
+  if (!password || !privateKey())
+    return setTimeout(function() {emit("messages")}, 1000) // try again later
+  show("allmessages")
+  notice("load messages, please wait …")
+  msgs.forEach(function(msg) {message(msg, true)})
+  show("chat")
+}
 
-  /// Received a message from server
-  function message(m, internal) {
-    if (!internal) console.log("rcv-> message("+m.user+")")
+/// Received a message from server
+function message(m, internal) {
+  if (!internal) console.log("rcv-> message("+m.user+")")
     if (!password || !privateKey()) return
-    var key=openpgp.key.readArmored(m.pubkey)
-    if (key.err) return error("key of sender unreadable", true)
+  var key=openpgp.key.readArmored(m.pubkey)
+  if (key.err) return error("key of sender unreadable", true)
     var message = openpgp.message.readArmored(m.msg)
-    var privkey = privateKey().keys[0]
-    if (privkey.decrypt(password)) // prepare own key
+  var privkey = privateKey().keys[0]
+  if (privkey.decrypt(password)) // prepare own key
+    openpgp.decrypt({
+      privateKeys: privkey,
+      publicKeys: key.keys,
+      message: message
+    }).then(function(msg) { // decryption succeded
       openpgp.decrypt({
         privateKeys: privkey,
         publicKeys: key.keys,
         message: message
       }).then(function(msg) { // decryption succeded
-        openpgp.decrypt({
-          privateKeys: privkey,
-          publicKeys: key.keys,
-          message: message
-        }).then(function(msg) { // decryption succeded
-          // prepend message to list of messages
-          var message = JSON.parse(msg.text)
-          $("#msgs") // todo: check msg.signatures[0].valid
-            .prepend('<div id="id'+(m.id)+'" class="msg '+
-                            (m.user==userid()?"me":"other")+
-                     '"><div class="header">'+
-                     '<span class="date">'+
-                            (new Date(m.time)).toLocaleString()+
-                     '</span><span class="sender">'+
-                     '<a href="javascript:void(0)" '+
-                     'onclick="setreceiver(this.innerHTML)">'+
-                     htmlenc(m.user)+
-                     '</a>'+(message.receiver?' → <a href="javascript:void(0)" '+
-                                              'onclick="setreceiver(this.innerHTML)">'
-                                             +htmlenc(message.receiver)+'</a>':"")+
-                     '</span></div>'+
-                     '<div class="text">'+
-                     htmlenc(message.text)+
-                     '</div></div><div class="clear"/>')
-          // show attachments
-          attachments(message.files, '#id'+m.id+' .text', m.user, new Date(m.time))
-          // calculate and show emoticons
-          $('#id'+m.id).emoticonize()
-          if (!internal) beep(m.user)
-        }).catch(function(e) {
-          // not for me
-          success()
-        })
-      }
+        // prepend message to list of messages
+        var message = JSON.parse(msg.text)
+        $("#msgs") // todo: check msg.signatures[0].valid
+                          .prepend('<div id="id'+(m.id)+'" class="msg '+
+                             (m.user==userid()?"me":"other")+
+                                   '"><div class="header">'+
+                                   '<span class="date">'+
+                             (new Date(m.time)).toLocaleString()+
+                                   '</span><span class="sender">'+
+                                   '<a href="javascript:void(0)" '+
+                                   'onclick="setreceiver(this.innerHTML)">'+
+                                   htmlenc(m.user)+
+                                   '</a>'+(message.receiver?' → <a href="javascript:void(0)" '+
+                                                            'onclick="setreceiver(this.innerHTML)">'
+                                                           +htmlenc(message.receiver)+'</a>':"")+
+                                   '</span></div>'+
+                                   '<div class="text">'+
+                                   htmlenc(message.text)+
+                                   '</div></div><div class="clear"/>')
+        // show attachments
+        attachments(message.files, '#id'+m.id+' .text', m.user, new Date(m.time))
+        // calculate and show emoticons
+        $('#id'+m.id).emoticonize()
+        if (!internal) beep(m.user)
+      }).catch(function(e) {
+        // not for me
+        success()
+      })
+    })
+}
 
-        /// Send Message To Server
-        /** User wants to send a message. Encrypt message with own private and
-           the receiver's public key, then send it to the server. */
-        function sendmessage(recv, txt) {
-          notice("1/3 preparing message …")
-          $("#message").prop(":disabled", true)
-          getPublicKey(recv) // get receiver's public key
-            .done(function(pk) {
-              var key=openpgp.key.readArmored(pk)
-              if (!pk||key.err) {
-                $("#message").prop(":disabled", false)
-                error("receiver's key not found", true)
-                return
-              }
-              var privkey = privateKey().keys[0]
-              privkey.decrypt(password) // get own private key ready
-              var message = JSON.stringify({receiver: recv, text: txt, files: filecontent})
-              notice("2/3 encrypting message …")
-              openpgp.encrypt({publicKeys: key.keys.concat(publicKey().keys),
-                               privateKeys: privkey,
-                               data: message,
-                               armor: false})
-                     .then(function(msg) { // message is encrypted
-                       notice("3/3 sending message …")
-                       emit("message", {user: userid(), content: msg})
-                       clearmessage()
-                     })
-                     .catch(function(e) {
-                       $("#message").prop(":disabled", false)
-                       error("encryption of message failed", true)
-                     })
-            })
-            .fail(function(e) {
-              $("#message").prop(":disabled", false)
-              error("user not found", true)
-            })
-        }
+/// Send Message To Server
+/** User wants to send a message. Encrypt message with own private and
+   the receiver's public key, then send it to the server. */
+function sendmessage(recv, txt) {
+  notice("1/3 preparing message …")
+  $("#message").prop(":disabled", true)
+  getPublicKey(recv) // get receiver's public key
+               .done(function(pk) {
+                 var key=openpgp.key.readArmored(pk)
+                 if (!pk||key.err) {
+                   $("#message").prop(":disabled", false)
+                   error("receiver's key not found", true)
+                   return
+                 }
+                 var privkey = privateKey().keys[0]
+                 privkey.decrypt(password) // get own private key ready
+                 var message = JSON.stringify({receiver: recv, text: txt, files: filecontent})
+                 notice("2/3 encrypting message …")
+                 openpgp.encrypt({publicKeys: key.keys.concat(publicKey().keys),
+                                  privateKeys: privkey,
+                                  data: message,
+                                  armor: false})
+                                   .then(function(msg) { // message is encrypted
+                                     notice("3/3 sending message …")
+                                     emit("message", {user: userid(), content: msg})
+                                     clearmessage()
+                                   })
+                                   .catch(function(e) {
+                                     $("#message").prop(":disabled", false)
+                                     error("encryption of message failed", true)
+                                   })
+               })
+               .fail(function(e) {
+                 $("#message").prop(":disabled", false)
+                 error("user not found", true)
+               })
+}
 
-        /// Check And Set Password
-        /** Check if given password matches to decrypt the private key. If so,
-           store it in global temporary variable @ref password and start the
-           chat. The password matches, when the private key can be decrypted.
-
-           @param pwd The password to check. */
-        function setpw(pwd) {
-          if (privateKey().keys[0].decrypt(pwd)) {
-            success("password matches")
-            $("#removeKey").hide()
-            password = pwd
-            chat()
-          } else {
-            notice("password does not match")
-          }
-        }
+/// Check And Set Password
+/** Check if given password matches to decrypt the private key. If so,
+   store it in global temporary variable @ref password and start the
+   chat. The password matches, when the private key can be decrypted.
+
+   @param pwd The password to check. */
+function setpw(pwd) {
+  if (privateKey().keys[0].decrypt(pwd)) {
+    success("password matches")
+    $("#removeKey").hide()
+    password = pwd
+    chat()
+  } else {
+    notice("password does not match")
+  }
+}
 
-        /// Create Password Entry Field
-        /** Asks user for password. When user starts to enter it, it is
-           permanentely checked in setpw(). As soon as the password matches,
-           setpw() continues automatically. No submit is required by the
-           user. */
-        function getpwd() {
-          if (password) return
-          $("#removeKey").show()
-          status("getpwd")
-        }
+/// Create Password Entry Field
+/** Asks user for password. When user starts to enter it, it is
+   permanentely checked in setpw(). As soon as the password matches,
+   setpw() continues automatically. No submit is required by the
+   user. */
+function getpwd() {
+  if (password) return
+  $("#removeKey").show()
+  show("getpwd")
+}
 
-        function deleteUser() {
-          var uid = userid()
-          localStorage.removeItem(pubkey)
-          localStorage.removeItem(privkey)
-          error("user "+uid+" permanentely lost")
-        }
+function deleteUser() {
+  var uid = userid()
+  localStorage.removeItem(pubkey)
+  localStorage.removeItem(privkey)
+  error("user "+uid+" permanentely lost")
+}
 
-        function removeKey() {
-          togglemenu()
-          $("#removeKey").hide()
-          status('forgotpassword')
-        }
+function removeKey() {
+  togglemenu()
+  $("#removeKey").hide()
+  show('forgotpassword')
+}
 
-        /// Main Chat Window
-        /** Gets chat widgets from server and displays them. Starts timer for
-           get() which polls for new messages. */
-        var firsttime = true
-        function chat() {
-          if (!password) return getpwd()
-          status("chat")
-          if (firsttime && $('#msgs').is(':empty')) {
-            firsttime = false
-            notice("getting previous messages, please wait …")
-            emit("messages")
-          }
-        }
+/// Main Chat Window
+/** Gets chat widgets from server and displays them. Starts timer for
+   get() which polls for new messages. */
+var firsttime = true
+function chat() {
+  if (!password) return getpwd()
+    show("chat")
+  if (firsttime && $('#msgs').is(':empty')) {
+    firsttime = false
+    notice("getting previous messages, please wait …")
+    emit("messages")
+  }
+}
 
-        /// Login User
-        /** This is not really a login, it is just some kind of validation.
-           The server does not care if a user is online or not, it is only
-           interesting to the client to make sure, everything is fine. User
-           is logged in the following way: User name and public key are sent
-           to the server. If the user name exists on the server and the
-           public key is the same, the user is considered logged in, his
-           credentials seem to be valid. If user does not yet exits on
-           server, it is created now. If user exists, but public key is
-           different, then this is a complete failure, something went
-           terribly wrong. */
-        function login() {
-          $("#username").html(userid()+"@"+hostname)
-          emit("login", {name: userid(),
-                         pubkey: localStorage.pubkey})
-          success("login sent to server")
-        }
+/// Login User
+/** This is not really a login, it is just some kind of validation.
+   The server does not care if a user is online or not, it is only
+   interesting to the client to make sure, everything is fine. User
+   is logged in the following way: User name and public key are sent
+   to the server. If the user name exists on the server and the
+   public key is the same, the user is considered logged in, his
+   credentials seem to be valid. If user does not yet exits on
+   server, it is created now. If user exists, but public key is
+   different, then this is a complete failure, something went
+   terribly wrong. */
+function login() {
+  $("#username").html(userid()+"@"+hostname)
+  emit("login", {name: userid(),
+                 pubkey: localStorage.pubkey})
+  success("login sent to server")
+}
 
-        /// Get And Display Form To Create New User
-        /** Shows user creation form. On submit, a private key is generated in
-           createkeypair(), then login() creates the user. */
-        function newuser() {
-          status("newuser")
-        }
+/// Get And Display Form To Create New User
+/** Shows user creation form. On submit, a private key is generated in
+   createkeypair(), then login() creates the user. */
+function newuser() {
+  show("newuser")
+}
 
-        /// Check if local storage is available
-        function checkLocalStorage() {
-          var test = 'test'
-          try {
-            localStorage.setItem(test, test)
-            localStorage.removeItem(test)
-            return true
-          } catch(e) {
-            status("nolocalstorage")
-            error("local storage not available")
-          }
-          return false
-        }
+/// Check if local storage is available
+function checkLocalStorage() {
+  var test = 'test'
+  try {
+    localStorage.setItem(test, test)
+    localStorage.removeItem(test)
+    return true
+  } catch(e) {
+    show("nolocalstorage")
+    error("local storage not available")
+  }
+  return false
+}
 
-        /// Initial Function: Startup
-        /** Decide whether to login or to create a new user */
-        function start() {
-          $("#menu").hide()
-          //status("startup")
-          if (checkLocalStorage())
-            try {
-              if (!userid()) {
-                newuser()
-              } else {
-                login()
-              }
-            } catch (m) {
-              console.log(m.stack)
-              error(m)
-            }
-        }
+/// Initial Function: Startup
+/** Decide whether to login or to create a new user */
+function start() {
+  $("#menu").hide()
+  //show("startup")
+  if (checkLocalStorage())
+    try {
+      if (!userid()) {
+        newuser()
+      } else {
+        login()
+      }
+    } catch (m) {
+      console.log(m.stack)
+      error(m)
+    }
+}
 
-        function init() {
-          /// On Load, Call @ref start
-          $(window.onbeforeunload = function() {
-            return "Are you sure you want to navigate away?"
-          })
-          /// Allow Running in Background on Android
-          document.addEventListener('deviceready', function () {
-            if (cordova && cordova.plugins.backgroundMode) {
-              cordova.plugins.backgroundMode.enable()
-            }
-          }, false)
-          connectionstatus()
-          if (openpgp.initWorker("openpgp.worker.min.js"))
-            console.log("asynchronous openpgp enabled")
-          else
-            console.log("asynchronous openpgp failed")
-          emit('users')
-          start()
-        }
+var safechat = new SafeChat()
+
+function init() {
+  safechat.start()
+}
+
+function old() {
+  /// On Load, Call @ref start
+  $(window.onbeforeunload = function() {
+    return "Are you sure you want to navigate away?"
+  })
+  /// Allow Running in Background on Android
+  document.addEventListener('deviceready', function () {
+    if (cordova && cordova.plugins.backgroundMode) {
+      cordova.plugins.backgroundMode.enable()
+    }
+  }, false)
+  connectionstatus()
+  if (openpgp.initWorker("openpgp.worker.min.js"))
+    console.log("asynchronous openpgp enabled")
+  else
+    console.log("asynchronous openpgp failed")
+  emit('users')
+  start()
+}
 
-        /// Start Main Loop
-        $(init)
+/// Start Main Loop
+$(init)
diff --git a/nodejs/public/stylesheets/safechat.css b/nodejs/public/stylesheets/safechat.css
index 32061a1..578d00f 100644
--- a/nodejs/public/stylesheets/safechat.css
+++ b/nodejs/public/stylesheets/safechat.css
@@ -58,7 +58,7 @@ form input#msg {
   height: 1.5em;
 }
 .toolbutton input {
-  display:none;
+  display: none;
 }
 .toolbutton.bad:first-line,
 .toolbutton.good:first-line {
diff --git a/nodejs/sockets/index.js b/nodejs/sockets/index.js
index 4ec8367..d9a5311 100644
--- a/nodejs/sockets/index.js
+++ b/nodejs/sockets/index.js
@@ -79,7 +79,7 @@ module.exports = function(sql) {
                 });
     });
     
-    socket.on("user", function(name) {
+    socket.on("user", function(name, fn) {
       console.log("-> signal: user("+name+")");
       var result = {name: name, exists: false, pubkey: null};
       sql.query("select pubkey from user where name = ?", [name], function(err, res, flds) {
@@ -87,10 +87,23 @@ module.exports = function(sql) {
           result.exists = true;
           result.pubkey = res[0].pubkey;
         }
-        emit('user', result);
+        fn(result);
       });
     });
     
+    socket.on("lookup", function(name, fn) {
+      console.log("-> signal: lookup("+name+")")
+      var result = false
+      sql.query("select pubkey from user where name = ?",
+                [name],
+                function(err, res, flds) {
+                  if (!err && res && res.length) {
+                    result = true;
+                  }
+                  fn(result)
+                });
+    });
+    
     socket.on("users", function(name) {
       console.log("-> signal: users");
       sql.query("select name, pubkey from user", [name], function(err, res, flds) {
diff --git a/nodejs/views/index.ejs b/nodejs/views/index.ejs
index 6726f08..a47160a 100644
--- a/nodejs/views/index.ejs
+++ b/nodejs/views/index.ejs
@@ -51,21 +51,12 @@
       <div id="newuser" style="display: none">
         <h2>Register User</h2>
         <p>All you need to start is a username and a password:</p>
-        <form id="register" autocomplete="off">
-          <input placeholder="username" autocomplete="off" type="text" id="user"/>
-          <input placeholder="password" autocomplete="off" type="password" id="pwd" oninput="checkpwd(this.value, document.getElementById('pwd2').value)"/>
-          <input placeholder="repeat password" autocomplete="off" type="password" id="pwd2" oninput="checkpwd(document.getElementById('pwd').value, this.value)"/>
-          <button id="createuser" disabled>register</button>
+        <form id="register" autocomplete="off" onsubmit="safechat.createuser(document.getElementById('user').value, document.getElementById('pwd').value)">
+          <input placeholder="username" autocomplete="off" type="text" id="user" oninput="safechat.lookup(this.value)" />
+          <input placeholder="password" autocomplete="off" type="password" id="pwd" oninput="safechat.checkpasswords(this.value, document.getElementById('pwd2').value)"/>
+          <input placeholder="repeat password" autocomplete="off" type="password" id="pwd2" oninput="safechat.checkpasswords(document.getElementById('pwd').value, this.value)"/>
+          <input id="createuser" type="submit" value="register" disabled />
         </form>
-        <script>
-          $("#user").on("input", function() {
-            queryuser($('#user').val());
-          });
-          $("#createuser").on("click", function(event) {
-            createkeypair($('#user').val(), $('#pwd').val());
-            return false;
-          });
-        </script>
         <p>Please chose any username, e.g. a pseudonym, your e-mail,
         your phone number, your real name, and chose a safe
         password.</p>
@@ -184,9 +175,9 @@
 
       <!--                                                    Fatal: Abort -->
 
-      <div id="fatal">
+      <div id="fatal" style="display: none">
         <h2 id="fatal-msg">Failure</h2>
-        <p>The SafeChat has been aborted due to a fatal error.</p>
+        <p>SafeChat has been aborted due to a fatal error.</p>
         <p>There is a problem in your browser. Please try to reload. If the problem persists, please update your web browser or try SafeChat in another browser.</p>
         <p>The following java script features are required:</p>
         <ul class="features">