function objetoAjax(){
	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 cargarPagina(url, capa){
	var capa = document.getElementById(capa);
	var ajax = new objetoAjax();
	
	ajax.open("GET",url, true);
	ajax.onreadystatechange = function(){
		if(ajax.readyState == 4){
			capa.innerHTML = ajax.responseText;
		}
	}
	ajax.send(null);
}