/* SOPORTE PARA FUNCIONALIDAD AJAX */
function getAjax(url) {
    var xmlHttp = null
    try {
        xmlHttp = new XMLHttpRequest()  // Firefox, Opera 8.0+, Safari
    } catch (e) {
        // Internet Explorer
        try {
            xmlHttp = new ActiveXObject("Msxml2.XMLHTTP")
        } catch (e) {
            xmlHttp = new ActiveXObject("Microsoft.XMLHTTP")
        }
    }
    xmlHttp.open ('POST', url, true);
    xmlHttp.setRequestHeader('Connection', 'close');
    xmlHttp.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
    
    return xmlHttp;
}