ASP.NET Atlas is full of JavaScript goodness

Jun 21, 2006 • ASP.NET • Javascript

I was looking through the JavaScript code for Atlas and I noticed there is some pretty neat stuff in there. It is really a very large enhancement to JavaScript.

One of the things I noticed is they are adding support for the XMLHttpRequest object if the browser doesn’t natively support it. In the past I’ve traditionally just created a function named similarly to CreateXMLHttpRequestObject and I make that function support multiple browsers. The technique that’s used in Atlas is they are adding the window.XMLHttpRequest object if it doesn’t already exist. This allows for your AJAX code to support multiple browsers more easily by making it so you don’t need to change your code to support Internet Explorer. And your code will still work in IE7 because IE7 natively supports the window.XMLHttpRequest object. Very nice guys!

Below is the above mentioned chunk of JS code for your viewing pleasure:

//-----------------------------------------------------------------------
// Copyright (C) Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------
// Atlas.js
// Atlas Framework.
//
if (!window.XMLHttpRequest) {
    window.XMLHttpRequest = function() {
        var progIDs = [ 'Msxml2.XMLHTTP', 'Microsoft.XMLHTTP' ];
     
        for (var i = 0; i < progIDs.length; i++) {
            try {
                var xmlHttp = new ActiveXObject(progIDs[i]);
                return xmlHttp;
            }
            catch (ex) {
            }
        }
     
        return null;
    }
}