javascript - can i get the html of the url by xmlhttprequest at clientside using javascript?

Question

I need to retreive the page source of the url using XMLhttpRequest in javascript.I tried it but i'm not getting any response. Following is my code and i'm getting blank response.text

function pagesource(url) {
    var request = makeHttpObject();
    request.open("GET", url, true);
    request.send(null);
    request.onreadystatechange = function () {
        if (request.readyState == 4) {
            if (request.status == 200) {
                alert(request.responseText);
            }
        }

    };   
}

function makeHttpObject() {
    try { return new XMLHttpRequest(); }
    catch (error) { }
    try { return new ActiveXObject("Msxml2.XMLHTTP"); }
    catch (error) { }
    try { return new ActiveXObject("Microsoft.XMLHTTP"); }
    catch (error) { }
    throw new Error("Could not create HTTP request object.");
}