//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.send(null);
	}
}

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);
	}
}

//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 */