<!-- Ajax sencillo personalizado por Eduardo de la Torre
function makeRequest(url,txt,capa) {

	var url;
	var txt;
	var capa;
	var now = new Date();
	var http_request = false;

        if (window.XMLHttpRequest) { // Mozilla, Safari,...
            http_request = new XMLHttpRequest();
            if (http_request.overrideMimeType) {
                http_request.overrideMimeType('text/xml');
            }
        } else if (window.ActiveXObject) { // IE
            try {
                http_request = new ActiveXObject("Msxml2.XMLHTTP");
            } catch (e) {
                try {
                    http_request = new ActiveXObject("Microsoft.XMLHTTP");
                } catch (e) {}
            }
        }

        if (!http_request) {
            alert('No puedo crear la instancia XMLHTTP');
            return false;
        }
        http_request.onreadystatechange = function() { alertContents(http_request,capa); };
        http_request.open('GET', url+'?c='+encodeURIComponent(capa)+'&t='+encodeURIComponent(txt)+'&rnd='+now.getTime(), true);
        http_request.send(null);

    }

    function alertContents(http_request,capa) {

		if (http_request.readyState == 1) {
			document.getElementById(capa).style.visibility = 'visible';
			document.getElementById(capa).innerHTML = '<span><img src="../cargando.gif" width="16" height="16" align=\"absmiddle\" /> Cargando datos...</span>';
		}
		
        else if (http_request.readyState == 4){
        
		    if (http_request.status == 200){
				var response = http_request.responseText;
        		var update = new Array();
        		if(response.indexOf('|' != -1)) {
					update = response.split('|');
					if(update[1] == 2) {
						document.getElementById(update[0]).style.display = 'none';
					}
					else{
						document.getElementById(update[0]).style.visibility = 'visible';
						document.getElementById(update[0]).innerHTML = update[1];
					}
				}
            }
			else{
                alert('Ha habido un problema con la solicitud\nInténtalo en unos minutos');
            }
        }
}
//-->