www.pudn.com > AjaxChatUchat.rar > AjaxFunctions.js

//Global variables 
var timeID; 
var refreshRate = 2000; // two seconds 
var rnd = Math.random(); 
 
var isFirefox; 
var isIE; 
 
//var XmlHttp; 
var AjaxServerPageName; 
AjaxServerPageName = "Server.aspx"; 
 
//Creating and setting the instance of appropriate XMLHTTP Request object to a “XmlHttp” variable   
function getAjax() 
{ 
	var XmlHttp; 
	 
	//Creating object of XMLHTTP in IE 
	try 
	{ 
		XmlHttp = new ActiveXObject("Msxml2.XMLHTTP"); 
	} 
	catch(e) 
	{ 
		try 
		{ 
			XmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); 
		}  
		catch(oc) 
		{ 
			XmlHttp = null; 
		} 
	} 
	//Creating object of XMLHTTP in Mozilla and Safari  
	if(!XmlHttp && typeof XMLHttpRequest != "undefined")  
	{ 
		XmlHttp = new XMLHttpRequest(); 
	} 
	return XmlHttp; 
} 
 
// Get browser type 
function sniffBrowserType() { 
	isFirefox = ( navigator.appName == "Netscape" ); 
	isIE = (navigator.appName == "Microsoft Internet Explorer" );  
} 
 
 
// Capture the enter key on the input box and post message 
function captureReturn( event ) 
{ 
	if(event.which || event.keyCode) 
	{ 
		if ((event.which == 13) || (event.keyCode == 13))  
		{ 
			postText(); 
			return false; 
		} 
		else { 
			return true; 
		} 
	}	 
} 
 
// Start the update timer 
function setTimers() 
{ 
	timeID = window.setTimeout( "updateAll()", refreshRate ); 
} 
 
// Start to update and reset the update timer 
function updateAll() 
{ 
	window.clearTimeout( timeID ); 
	getUserList(); 
	setTimers(); 
} 
 
function getUserList() 
{ 
	rnd++; 
	url = 'Server.aspx?action=UserList&session=' + rnd; 
	req = getAjax(); 
 
	req.onreadystatechange = function(){ 
	 
		if( req.readyState == 4 && req.status == 200 ) { 
		 
			obj = getElement( "userlist" ); 
			obj.innerHTML = req.responseText; 
			getBufferText(); 
		} 
	 
	} 
	 
	req.open( 'GET', url, true ); 
	req.send( null ); 
} 
 
function getBufferText() 
{ 
    rnd++; 
	url = 'Server.aspx?action=GetMsg&session=' + rnd; 
	req = getAjax(); 
	 
	req.onreadystatechange = function(){ 
	 
		if( req.readyState == 4 && req.status == 200 ) { 
		 
			obj = getElement( "chatbuffer" ); 
			obj.innerHTML = req.responseText; 
			scrollChatPane(); 
			//FocusWindow(); 
		} 
	} 
	 
	req.open( 'GET', url , true ); 
	req.send( null ); 
} 
 
function postText() 
{ 
	rnd++; 
	chatbox = getElement( "mytext" ); 
	chat = chatbox.value; 
	chatbox.value = ""; 
	 
	userid = location.search.substring( 1, location.search.length ); 
	url = 'Server.aspx?action=PostMsg&u=' + userid + '&t=' + encodeURIComponent(chat) + '&session=' + rnd; 
	 
	req = getAjax(); 
	 
	req.onreadystatechange = function(){ 
	 
		if( req.readyState == 4 && req.status == 200 ) { 
			updateAll(); 
		} 
	 
	} 
	 
	req.open( 'GET', url, true ); 
	req.send( null ); 
} 
 
function getElement( id )  
{ 
	if( isIE ) { 
		return document.all[ id ]; 
	} 
	else { 
		return document.getElementById( id ); 
	} 
} 
 
function showLoadScreen() 
{ 
	var loading = "
Loading...
"; 
 
	chat = getElement( "chatbuffer" ); 
	chat.innerHTML = loading; 
	 
	user = getElement( "userlist" ); 
	user.innerHTML = loading; 
} 
 
function scrollChatPane() 
{ 
	var obj = document.getElementById("chatpane"); 
	obj.scrollTop = obj.scrollHeight; 
} 
 
function setFocus(ControlName) 
{ 
	var control = document.getElementById(ControlName); 
	if( control != null ) 
	{ 
		control.focus(); 
	} 
} 
function FocusWindow() 
{ 
 
	//TODO: FireFox doesn't work? 
	window.focus(); 
 
}