var bustcachevar=1 // bust potential caching of external pages after initial request? (1=yes, 0=no)
var loadstatustext="<img src='http://www.instanthmi.com/images/tabs/loading.gif' /> Please wait loading...";

/////////////////////////////////////////////////
var loadedobjects       = "";
var defaultcontentarray = new Object();
var bustcacheparameter  = "";

function ajaxpage( url, containerid, targetobj )
{
var page_request = false
if (window.XMLHttpRequest) // if Mozilla, Safari etc
	{
	page_request = new XMLHttpRequest();
	}
else if( window.ActiveXObject )
	{ // if IE
	try 
		{
		page_request = new ActiveXObject("Msxml2.XMLHTTP");
		} 
	catch (e)
		{
		try
			{
			page_request = new ActiveXObject("Microsoft.XMLHTTP");
			}
		catch (e){}
		}
	}
else
	{
	return false;
	}

var ullist = targetobj.parentNode.parentNode.getElementsByTagName("li");
for( var i = 0; i < ullist.length; i++ )
	{
	ullist[i].className = "";  // deselect all tabs
	}

targetobj.parentNode.className = "selected"  // highlight currently clicked on tab
if( url.indexOf("#default") != -1 )
	{ //if simply show default content within container (verus fetch it via ajax)
	document.getElementById(containerid).innerHTML = defaultcontentarray[containerid];
	return;
	}

document.getElementById(containerid).innerHTML = loadstatustext;
page_request.onreadystatechange = function()
	{
	loadpage( page_request, containerid );
	}

if( bustcachevar ) // if bust caching of external page
	{
	bustcacheparameter = (url.indexOf("?")!=-1)? "&"+new Date().getTime() : "?"+new Date().getTime();
	}
page_request.open( 'GET', url+bustcacheparameter, true );
page_request.send( null );
}

function loadpage( page_request, containerid )
{
if( page_request.readyState == 4 && ( (page_request.status == 200) || (window.location.href.indexOf("http") == -1) ) )
	{
	document.getElementById(containerid).innerHTML = page_request.responseText;
	}
}

function loadobjs( revattribute )
{
	// if "rev" attribute is defined (load external .js or .css files)
if( (revattribute != null) && (revattribute != "") )
	{ 
	var objectlist=revattribute.split(/\s*,\s*/); // split the files and store as array
	for( var i = 0; i < objectlist.length; i++ )
		{
		var file = objectlist[i];
		var fileref = "";
		if( loadedobjects.indexOf(file) == -1 )
			{ //Check to see if this object has not already been added to page before proceeding
			if( file.indexOf(".js") != -1 )
				{ //If object is a js file
				fileref = document.createElement( 'script' );
				fileref.setAttribute( "type", "text/javascript" );
				fileref.setAttribute( "src", file );
				}
			else if( file.indexOf(".css") != -1 )
				{ //If object is a css file
				fileref = document.createElement( "link" );
				fileref.setAttribute( "rel", "stylesheet" );
				fileref.setAttribute( "type", "text/css" );
				fileref.setAttribute( "href", file );
				}
			}
		
		if( fileref != "" )
			{
			document.getElementsByTagName("head").item(0).appendChild(fileref);
			loadedobjects += file + " "; // Remember this object as being already added to page
			}
		}
	}
}

	// save default ajax tab content
function savedefaultcontent( contentid )
{
if( typeof defaultcontentarray[contentid] == "undefined" ) //if default content hasn't already been saved
	{	
	defaultcontentarray[contentid] = document.getElementById(contentid).innerHTML;
	}
}

function startajaxtabs()
{
for( var i = 0; i < arguments.length; i++ )
	{ //loop through passed UL ids
	var ulobj = document.getElementById( arguments[i] );
	var ulist = ulobj.getElementsByTagName("li"); //array containing the LI elements within UL
	for( var x = 0; x < ulist.length; x++ )
		{ //loop through each LI element
		var ulistlink = ulist[x].getElementsByTagName("a")[0];
		if( ulistlink.getAttribute("rel") )
			{
			var modifiedurl = ulistlink.getAttribute("href").replace(/^http:\/\/[^\/]+\//i, "http://"+window.location.hostname+"/");
			ulistlink.setAttribute( "href", modifiedurl ); 		// replace URL's root domain with dynamic root domain, for ajax security sake
			savedefaultcontent( ulistlink.getAttribute("rel") ); 	//save default ajax tab content
			ulistlink.onclick=function()
				{
				ajaxpage( this.getAttribute("href"), this.getAttribute("rel"), this );
				loadobjs( this.getAttribute("rev") );
				return false;
				}

			if( ulist[x].className == "selected" )
				{
				ajaxpage( ulistlink.getAttribute("href"), ulistlink.getAttribute("rel"), ulistlink ); // auto load currenly selected tab content
				loadobjs( ulistlink.getAttribute("rev") ); //auto load any accompanying .js and .css files
				}
			}
		}
	}
}