var http_request = false;
    function makeRequest(url,contenido) {
        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('Falla :( No es posible crear una instancia XMLHTTP');
            return false;
        }
        http_request.open('GET', url, contenido, true);
        http_request.onreadystatechange = function () {
			if (http_request.readyState == 4 && http_request.status == 200) {
					var destino = document.getElementById(contenido);
					destino.innerHTML = http_request.responseText;
				}
        }
        http_request.send(null);
    }