Chat SCF Behavior Script

/*
 Chat Smartlet enrichment script
*/
$j.scf.behavior.add('sml_chat_Behavior', {
 attach: function(e,settings,j){
  var frm = j.find('form'); // find form element under jQuery selector
  
  // create/extend settings object passed to the behavior
  // using Object extension
  settings = Object.extend({
   joinMessage: 'Joined the chat',
   createMessage: 'New chat started!'
  }, settings);
 
  var smartlet = $j.scf.smartlet.get(e); // get Smartlet object from div with Smartlet ID.
  var div = $j('.ChatHistory', e), speak = $j('.Speak', e), send = $j('.Send', e);
  var clear = $j('.Clear', e), tmr;
  
  // setup focus and blur event handlers
  speak.focus(function(){
   clearTimeout(tmr); // do not poll when textbox has focus
   send.attr('value', 'Send'); // update the Send button
  });
  
  speak.blur(function(){
   tmr = setTimeout(update, 5000); // reset poll timeout
   send.attr('value', 'Refresh'); // update the Send button
  });
  
  // Add message to conversation div
  function addData(html){
   if(html && typeof(html) == 'string' && html.trim().length){
    // create and fade in new line(s) of text
    var row = $j(html).hide();
    div.append(row);
    row.fadeIn(200);
    
    // scroll last line into view
    if(row && row[row.length-1] && row[row.length-1].scrollIntoView)
     row[row.length-1].scrollIntoView();
   }
  }
  
  // update user interface
  function update(){
   clearTimeout(tmr); // clear timer
   
   if(settings.isAnonymous)
    return;
   // Do the actual Ajax call to the server-side Smartlet
   // and update the user interface with conversation data
   // if returned
   smartlet.ajax(function(o){
    addData(smartlet.get('data'));
    // reset the refresh poll interval
    tmr = setTimeout(update, settings.refreshInterval || 5000);
   });
  }
  
  // send message to server-side chat room
  function sendString(phrase, sysmsg){
   smartlet.set('sysmsg', (sysmsg==true)); // is it a system message?
   smartlet.set('phrase', phrase); // the line of text to send
   speak.val(''); // clear the message textbox
   update(); // update user-interface
   smartlet.set('phrase',''); //clear message
  }
  
  // modify standard form submit handler for Ajax
  frm.submit(function(event){
   var s = speak.val().trim(); // get message from textbox
   if(s && s.length)
    sendString(s); // send it
   return false; // suppress standard form submit handler
  });
  
  // setup event handler for Clear button
  clear.click(function(event){
   if(!(settings.confirmClear==true) || confirm(settings.confirmClearMessage || 'Clear window?')){
    div.html(''); // clear the conversation pane
    sendString(''); // send empty string to update user message index
   }
   return false;
  });
  // send join/create message at startup, depending on the message count in the current chat room.  
  setTimeout(function(){
   sendString((settings.firstPost==-1) ? (settings.count ? settings.joinMessage : settings.createMessage) : '', true);
  }, 1);
  
  // disable user interface if no user logged on
  if(settings.isAnonymous){
   if(!settings.allowAnonymous)
    $j('.sml_chat .Control').attr('disabled', true);
  }
 }
});