function nuevoAjax(){ 
	var xmlhttp=false;
	try {
		xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
	} 
	catch (e) {
		try {
			xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
		} catch (E) {
			xmlhttp = false;
		}
	}
	if (!xmlhttp && typeof XMLHttpRequest!='undefined') {
		xmlhttp = new XMLHttpRequest();
	}
	return xmlhttp;
}

function cargar(destino,refresco,valores,sustituir,img){
alert('hola');
	var principal = nuevoAjax();
	var valores = valores;
	var destino = destino + '.php';
	var contenedor = document.getElementById(refresco);
	var contenido = contenedor.innerHTML;
	principal.onreadystatechange = function(){
		if (principal.readyState == 4 && principal.status == 200){
			if (sustituir == true)
				contenedor.innerHTML = principal.responseText; 
			else{
				if (img==3){
					document.getElementById('carganext').innerHTML = "";
					document.getElementById(refresco).innerHTML = "";
				}			
				contenedor.innerHTML = contenido + principal.responseText; 	
			}
			//if (valores == 'loc=error' && principal.responseText != ''){
				//mostrarDiv('error');
				//mostrarDiv('fondoerror');
			//}
		} else { 				
			if (img==1){
				contenedor.innerHTML = "<center>Enviando, por favor espere...<br/><img src='../Images/loading.gif'></center>" 
			}if (img==2){
				contenedor.innerHTML = "<br><center><img src='../Images/loading1.gif'></center><br>"	
			}if (img==3){
				contenedor.innerHTML = "<p><center>Cargando, por favor espere...<br><img src='../Images/loading.gif'></center></p>"	
			}
		}
	}
	principal.open("POST" , destino , true);
	principal.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
	principal.send(valores);	
}