function ajaxInit() {
		var req;
		
		try {
	 req = new ActiveXObject("Microsoft.XMLHTTP");
		} catch(e) {
	 try {
		 req = new ActiveXObject("Msxml2.XMLHTTP");
	 } catch(ex) {
		 try {
	   req = new XMLHttpRequest();
		 } catch(exc) {
	   alert("Esse browser não tem recursos para uso do Ajax");
	   req = null;
		 }
	 }
		}
		
		return req;
	}
	function verifica(lab, url) {
	 label = document.getElementById(lab);
	 ajax = ajaxInit();	 
	 if(ajax) {
	   ajax.open("get", url, true);
	   ajax.onreadystatechange = function() {
	   if (ajax.readyState==1){
	   	document.getElementById(lab).style.visibility = 'visible';
		label.innerHTML = "<img src='images/loader.gif' /><small style:'color:white;'>carregando</small>"; 
	}
	 if(ajax.readyState == 4) {
		   label.innerHTML = ajax.responseText; 
		 }
	   }
	   ajax.send(null);
	 }
	}