function DoAjax(url) {
	if(window.XMLHttpRequest) // FIREFOX
		xhr_object = new XMLHttpRequest();
	else if(window.ActiveXObject) // IE
		xhr_object = new ActiveXObject("Microsoft.XMLHTTP");
	else
		return(false);	
	
	xhr_object.open("GET", '/_ajax/'+url, false);
	xhr_object.send(null);	

	if(xhr_object.readyState == 4){
		var res = xhr_object.responseText;
		//alert(res);
		return res;
	}
	else
		return "<div class=\"red_box\">This Operation cannot be performed for the moment</div>";
}

function GetId(id) {
	if(document.getElementById) // standardised method first
		return document.getElementById(id);
	else if(document.all)
		return document.all[id];
	else if(document.layers)
		return document.layers[id];
	else
		return null;
}


function GetSel(id){
	return GetId(id).options[GetId(id).selectedIndex].value;
}

function CheckField(field,classes,msg){
	GetId(field+'_box').innerHTML = msg;
	if(GetId(field))
	GetId(field).className = classes;
	GetId(field+'_box').className = classes;
}

function CountErrors(form_id){
	var err = 0;
	var cur_form = document.getElementById(form_id);
	var spans = document.getElementsByTagName('span');
	for(i=0;i!=spans.length;i++){
		if(spans[i].className == 'error')
			err++;
	}
	if(err == 0) return(true); else return(false);
}

function Popup(url){
window.open( url, "Popup", 
"status = 0, height = 600, width = 700, resizable = 0, scrollbars = 1"  );
}