/**
 * @author sara
 */
function getXMLHTTP(){
    var xmlhttp = false;
    try {
        xmlhttp = new XMLHttpRequest();
    } 
    catch (e) {
        try {
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        } 
        catch (e) {
            try {
                xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
            } 
            catch (e1) {
                xmlhttp = false;
            }
        }
    }
    
    return xmlhttp;
}