Question

Is there any real advantage to using the jQuery AJAX function over the type of AJAX function shown below? Obviously, the syntax is a little cleaner / shorter – but is there any noticiable difference that would justify re-writing my existing ajax code?

var ajax = getXmlObject();
var url= '/addPartToCart.php?m=' + encodeURIComponent(m) + 
         '&q=' + qty + 
         '&refresh=' + randomString();

if (ajax.readyState == 4 || ajax.readyState == 0) {
    ajax.open("POST", url, true);
    ajax.onreadystatechange = function (){
        if (ajax.readyState == 4) {    

        }
    }; 
    ajax.send(null);
} 

function getXmlObject() {
    if (window.XMLHttpRequest) {
        return new XMLHttpRequest();
    } else if(window.ActiveXObject) {
        return new ActiveXObject("Microsoft.XMLHTTP");
    } else {
        //error
    }
}

UPDATE

I’ve reprogrammed all of my AJAX functions to use jQuery’s .ajax(). I must say I’ve seen a notable improvement in speed and reliability.

Answer 1

You may want to give a look to jQuery’s src/ajax.js source code. One reason it’s 720 sloc, and not just 10 is mainly to:

• Fix and wrap known inconsistencies between the different browsers. The comments will reveal many of these issues.

• Provide extra features like handling JSONP through the same interface, event hooks, etc. And other syntactic sugar.