//Basic Ajax Routine- Author: Dynamic Drive (http://www.dynamicdrive.com)
//Last updated: Jan 15th, 06'

function createAjaxObj(){
	var httprequest=false;
	if (window.XMLHttpRequest){ // if Mozilla, Safari etc
		httprequest=new XMLHttpRequest();
		if (httprequest.overrideMimeType)
			httprequest.overrideMimeType('text/xml');
	}
	else if (window.ActiveXObject){ // if IE
		try {
			httprequest=new ActiveXObject("Msxml2.XMLHTTP");
		} 
		catch (e){
			try{
				httprequest=new ActiveXObject("Microsoft.XMLHTTP");
			}
			catch (e){}
		}
	}
	return httprequest;
}

var ajaxpack=new Object();
ajaxpack.basedomain="http://"+window.location.hostname;
ajaxpack.ajaxobj=createAjaxObj();
ajaxpack.filetype="txt";
ajaxpack.addrandomnumber=1; //Set to 1 or 0. See documentation.

ajaxpack.getAjaxRequest = function(url, parameters, callbackfunc, filetype){
	ajaxpack.ajaxobj=createAjaxObj(); //recreate ajax object to defeat cache problem in IE
	if (ajaxpack.addrandomnumber==1) //Further defeat caching problem in IE?
		var parameters=parameters+"&ajaxcachebust="+new Date().getTime();
	if (this.ajaxobj){
		this.filetype=filetype;
		this.ajaxobj.onreadystatechange = callbackfunc;  
		this.ajaxobj.open('GET', url+"?"+parameters, true);
		//this.ajaxobj.setRequestHeader("Content-type", "application/xml");
		//this.ajaxobj.setRequestHeader("Pragma", "no-cache");
		//this.ajaxobj.setRequestHeader("Cache-Control", "must-revalidate");
		//this.ajaxobj.setRequestHeader("If-Modified-Since", document.lastModified);
		this.ajaxobj.send(null);
		return true;
	}
	return false;
}

ajaxpack.ajaxLocation = function(url, parameters){

	
	ajaxpack.ajaxobj=createAjaxObj(); //recreate ajax object to defeat cache problem in IE
	//if (ajaxpack.addrandomnumber==1) //Further defeat caching problem in IE?
		//var parameters=parameters+"&ajaxcachebust="+new Date().getTime();
	if (this.ajaxobj){
		this.ajaxobj.open('POST', url, false);
		this.ajaxobj.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
		this.ajaxobj.setRequestHeader("Content-length", parameters.length);
		//this.ajaxobj.setRequestHeader("Connection", "close");	
		this.ajaxobj.send(parameters);
		
		//this.ajaxobj.open('GET', url+'?'+parameters, false);
		//this.ajaxobj.send(null);
		
		return true;
	}
	return false;
}

ajaxpack.postAjaxRequest=function(url, parameters, callbackfunc, filetype){
	ajaxpack.ajaxobj=createAjaxObj(); //recreate ajax object to defeat cache problem in IE
	if (this.ajaxobj){
		this.filetype=filetype;
		this.ajaxobj.onreadystatechange = callbackfunc;
		this.ajaxobj.open('POST', url, true);
		this.ajaxobj.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
		this.ajaxobj.setRequestHeader("Content-length", parameters.length);
		this.ajaxobj.setRequestHeader("Connection", "close");
		this.ajaxobj.send(parameters);
		return true;
	}
	return false;
}

//ACCESSIBLE VARIABLES (for use within your callback functions):
//1) ajaxpack.ajaxobj //points to the current ajax object
//2) ajaxpack.filetype //The expected file type of the external file ("txt" or "xml")
//3) ajaxpack.basedomain //The root domain executing this ajax script, taking into account the possible "www" prefix.
//4) ajaxpack.addrandomnumber //Set to 0 or 1. When set to 1, a random number will be added to the end of the query string of GET requests to bust file caching of the external file in IE. See docs for more info.

//ACCESSIBLE FUNCTIONS:
//1) ajaxpack.getAjaxRequest(url, parameters, callbackfunc, filetype)
//2) ajaxpack.postAjaxRequest(url, parameters, callbackfunc, filetype)

///////////END OF ROUTINE HERE////////////////////////


//////EXAMPLE USAGE ////////////////////////////////////////////
/* Comment begins here

//Define call back function to process returned data
function processGetPost(){
var myajax=ajaxpack.ajaxobj
var myfiletype=ajaxpack.filetype
if (myajax.readyState == 4){ //if request of file completed
if (myajax.status==200 || window.location.href.indexOf("http")==-1){ if request was successful or running script locally
if (myfiletype=="txt")
alert(myajax.responseText)
else
alert(myajax.responseXML)
}
}
}

/////1) GET Example- alert contents of any file (regular text or xml file):

ajaxpack.getAjaxRequest("example.php", "", processGetPost, "txt")
ajaxpack.getAjaxRequest("example.php", "name=George&age=27", processGetPost, "txt")
ajaxpack.getAjaxRequest("examplexml.php", "name=George&age=27", processGetPost, "xml")
ajaxpack.getAjaxRequest(ajaxpack.basedomain+"/mydir/mylist.txt", "", processGetPost, "txt")

/////2) Post Example- Post some data to a PHP script for processing, then alert posted data:

//Define function to construct the desired parameters and their values to post via Ajax
function getPostParameters(){
var namevalue=document.getElementById("namediv").innerHTML //get name value from a DIV
var agevalue=document.getElementById("myform").agefield.value //get age value from a form field
var poststr = "name=" + encodeURI(namevalue) + "&age=" + encodeURI(agevalue)
return poststr
}

var poststr=getPostParameters()

ajaxpack.postAjaxRequest("example.php", poststr, processGetPost, "txt")
ajaxpack.postAjaxRequest("examplexml.php", poststr, processGetPost, "xml")

Comment Ends here */