var ajax_xmlHttp;
var ajax_is_ie = (navigator.userAgent.indexOf('MSIE') >= 0) ? 1 : 0;
var ajax_is_ie5 = (navigator.appVersion.indexOf("MSIE 5.5")!=-1) ? 1 : 0;
var ajax_is_opera = (navigator.userAgent.indexOf("Opera")!=-1) ? 1 : 0;
//netscape, safari, mozilla 
var ajax_is_netscape = (navigator.userAgent.indexOf('Netscape') >= 0) ? 1 : 0;

// XMLHttp send GET request
function xmlHttp_Get(xmlhttp, url) {
    xmlhttp.open('GET', url, true);
    xmlhttp.send(null);
}

function GetXmlHttpObject(handler) {
    var objXmlHttp = null;    //Holds the local xmlHTTP object instance

    //Depending on the browser, try to create the xmlHttp object
    if (ajax_is_ie){
        //The object to create depends on version of IE
        //If it isn't ie5, then default to the Msxml2.XMLHTTP object
        var strObjName = (ajax_is_ie5) ? 'Microsoft.XMLHTTP' : 'Msxml2.XMLHTTP';
        
        //Attempt to create the object
        try{
            objXmlHttp = new ActiveXObject(strObjName);
            objXmlHttp.onreadystatechange = handler;
        }
        catch(e){
        //Object creation errored
            alert('Erro ! Verifique que tem JavaScript e activeX activado');
            return;
        }
    }
    else{
        // Mozilla | Netscape | Safari
        objXmlHttp = new XMLHttpRequest();
        objXmlHttp.onload = handler;
        objXmlHttp.onerror = handler;
    }
    
    //Return the instantiated object
    return objXmlHttp;
}