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 llamar(id,pagina,datos){
	contenedor = document.getElementById(id);
	ajax=nuevoAjax();
	ajax.open("POST", pagina,true);
	ajax.onreadystatechange=function() {
		if (ajax.readyState==4) {
			contenedor.innerHTML = ajax.responseText
		}
	}
	ajax.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
	ajax.send(datos);
}