function ajaxFunction(){
	try{
		// Opera 8.0+, Firefox, Safari
		ajaxRequest = new XMLHttpRequest();
	} catch (e){
		// Internet Explorer Browsers
		try{
			ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try{
				ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e){
				// Something went wrong
				alert("Your browser broke!");
				return false;
			}
		}
	}
	return true;
}


function ajaxAction(url, preloader, categorySelect){
	var preloader = document.getElementById(preloader);
	if ( ajaxFunction() ){
		var run = true;
		ajaxRequest.onreadystatechange = function(){
			if (preloader && preloader.style.display=="none"){
				preloader.style.display="block";					
			}
			if ( ajaxRequest.readyState == 4 && ajaxRequest.status == 200) {
				//alert(ajaxRequest.responseText);
				var xmldoc = ajaxRequest.responseXML;
				if (!xmldoc) return false;
				
				categories = xmldoc.getElementsByTagName("category");
				var n = categories.length;
				for ( var i=0; i<n; i++){
					var category_id = categories[i].getAttribute('id');
					var categoryName = categories[i].getAttribute('name');
					categorySelect.options[i+1] = new Option(categoryName,category_id);
				}
				
				if (preloader) {
					preloader.style.display = "none";
				}
			}
			else {
				//ajaxDisplay.innerHTML = "";
			}
			
		}
		
		ajaxRequest.open("GET", url, true);
		ajaxRequest.send(null);
	}
}