function newAjax() {
	var XMLHttp = false;
	if (window.XMLHttpRequest) {
		// Si es Mozilla, Safari etc
		XMLHttp = new XMLHttpRequest ();
	} else {
		if (window.ActiveXObject) {
			// pero si es IE
		try {
			XMLHttp = new ActiveXObject ("Msxml2.XMLHTTP");
		} catch (e) {
				// en caso que sea una versión antigua
			try {
				XMLHttp = new ActiveXObject ("Microsoft.XMLHTTP");
			} catch (e) {
				return false;
			}
		}
		} else {
		return false;
		}
	} 
	 return XMLHttp;
}

function cargarContenidoAjaxPOST(url, post, contenedor) { 
	ajax = newAjax(); 
	if (ajax==false) {
		alert("Exception AJAX");
		return;
	} 
	ajax.open("POST",url,true); 
	ajax.onreadystatechange=function() {  
		if (ajax.readyState == 4 && (ajax.status == 200 || window.location.href.indexOf ("http") == - 1)) { 
		contenedor.innerHTML = ajax.responseText;
		if(document.getElementById('loadingGif')){
			mostrarLoading();
		}
		}  
	}
	ajax.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
	ajax.send(post);
}

function cargarContenidoAjaxPOSTNoReturn(url, post) { 
	ajax = newAjax(); 
	if (ajax==false) {
		alert("Exception AJAX");
		return;
	} 
	ajax.open("POST",url,true); 
	ajax.onreadystatechange=function() { 
		if (ajax.readyState == 4 && (ajax.status == 200 || window.location.href.indexOf ("http") == - 1)) { 
		}
		}  
	ajax.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
	ajax.send(post);
}