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;

}

//------------------------------------------------------------------------

// FUNCIONES DE CARGA

//------------------------------------------------------------------------

function cargarPost(div,page,atrib){

	var divResultado = document.getElementById(div);

	var ajax=objetoAjax();

	ajax.open("POST", page, true);

	ajax.onreadystatechange=function(){

	switch(ajax.readyState){

		case 1: // loading

			document.getElementById('ajax_loading').style.top = "290px";

			document.getElementById('ajax_loading').style.left = ((screen.width)/2) + "px";

			document.getElementById('ajax_loading').style.display = "block";

			break;

		case 4: // complete

			divResultado.innerHTML = ajax.responseText;

			document.getElementById('ajax_loading').style.display = "none";

			break;

		}

	}

	ajax.setRequestHeader("Content-Type","application/x-www-form-urlencoded");

	ajax.send(atrib);

}

function cargarGet(div,page,atrib){

	var divResultado = document.getElementById(div);

	var ajax=objetoAjax();

	if(atrib!=""){ page = page + '?' + atrib; }

	ajax.open("GET", page);

	ajax.onreadystatechange=function(){

		if (ajax.readyState==4) {

			divResultado.innerHTML = ajax.responseText;

		}

	}

	ajax.send(null);

}

//------------------------------------------------------------------------

//Funcion para CARGAR los cursos de un canal

//------------------------------------------------------------------------

function cargarModelos(div,url,marca,value){
	var divResultado = document.getElementById(div);
	var ajax=objetoAjax();
	var atrib='marca='+marca+'&value='+value;
	ajax.open("POST", url, true);
	ajax.onreadystatechange=function(){
		if (ajax.readyState==4) {
			var txt = ajax.responseText;
			divResultado.innerHTML = txt;
			if(txt=="No hay marcas para esta categoria."){
				cargarModelos('divModelos','listarModelos.php','','');
			}
		}
	}
	ajax.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
	ajax.send(atrib);

}