/**
 * Using Object Detection for a Cross-Browser Solution
 */
function getXmlHttpObject()
{
	var obj = null;

	try
	{
		obj = new XMLHttpRequest();
		// e.g. Firefox
	}
	catch(err1)
	{
		try
		{
			obj = new ActiveXObject("Msxml2.XMLHTTP");
			// some versions IE
		}
		catch(err2)
		{
			try
			{
				obj = new ActiveXObject("Microsoft.XMLHTTP");
				// some versions IE
			}
			catch(err3)
			{
			}
		}
	}

	return obj;
}



/**
 * XML HTTP object
 */
var xmlHttp;



/**
 * Send Ajax request using POST
 *
 * @param string url the URL to post the request to
 * @param string parameters the parameters to send with the request
 * @param string callback the name of the function to use for callback
 */
function postAjax(url, parameters, callback)
{
	xmlHttp = getXmlHttpObject();

	if(xmlHttp)
	{
		try
		{
			rnd = (new Date().getTime()) + parseInt(Math.random()*99999999);

			xmlHttp.onreadystatechange = callback;
			xmlHttp.open("POST", url, true);
			xmlHttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
			xmlHttp.send(parameters + '&random=' + rnd);
		}
		catch(e)
		{
		}
	}
}



/**
 * Ajax callback function
 *
 * @param string element the name of the element to print the reponse in
 * @param integer graphics the loading graphics to display
 * @param integer type the type of loading graphics (1=graphics are loaded in same element the response is loaded, 2=full screen loading page)
 *
 * @return boolean status true if callback complete, false if not
 */
function callbackAjax(element, graphics, type)
{
	var status = false;

	//check if state is "loaded"
	if(xmlHttp.readyState == 4)
	{
		//check if server HTTP response is "OK"
		if(xmlHttp.status == 200)
		{
			//close loading popup (if applicable)
			if(type == 2)
			{
					 if(			  document.getElementById('popupWindow2'))	{			   document.getElementById('popupWindow2').innerHTML = '';}
				else if(window.parent.document.getElementById('popupWindow2'))	{window.parent.document.getElementById('popupWindow2').innerHTML = '';}
				obj_lib_popup = new lib_Popup();
				obj_lib_popup.closePopUp(2);
			}

			//print response
			document.getElementById(element).innerHTML = xmlHttp.responseText;
			status = true;
		}
		else
		{
			//display error message
			document.getElementById(element).innerHTML = 'ERROR';
		}
	}
	else
	{
		//while waiting for the page to load, display loading graphics(html)

		//get selected loading graphics
		var html = '';
		     if	(graphics == 1)	{html = '<img src="ajax-loader.gif"> Pagina wordt geladen...';}
		else if (graphics == 2)	{html = '<center><img src="ajax-loader.gif"> Pagina wordt geladen...</center>';}
		else if (graphics == 3)	{html = '';}

		if(type == 1)
		{
			//display selected graphics in appropriate element
			document.getElementById(element).innerHTML = html;
		}
		else
		{
			//clear result element
			document.getElementById(element).innerHTML = '';

			//open popup
			obj_lib_popup = new lib_Popup();
			obj_lib_popup.openPopUp(2, 100, 100);

			//display selected graphics in popup
				 if(			  document.getElementById('popupWindow2'))	{			   document.getElementById('popupWindow2').innerHTML = html;}
			else if(window.parent.document.getElementById('popupWindow2'))	{window.parent.document.getElementById('popupWindow2').innerHTML = html;}
		}
	}

	return status;
}