Microsoft has finally released IE7. It offers a lot of improvements over IE6 for both users and developers. A lot of bugs related to layout, CSS and memory leaks were fixed. I got really excited when I installed it thinking that most of my problems are over, but life is never perfect. I spent almost a whole day trying to figure out how to work around a new problem that appeared with IE7.

New Internet Explorer introduces native XMLHTTP (used to communicate with server behind the scene without page refresh) support. Up to and including IE6 developers had to use ActiveX object that came with MSXML. Native support makes IE more compatible with other browsers (script is easier to reuse between browsers), but more importantly it is faster and allows XMLHTTP to work even when ActiveX is disabled.

This new feature became a source of frustration for me. Microsoft is tightening security screws and new XMLHTTP denies local files access. In general I think this is wise, but there are exceptions where access to the local files is needed.

When I'm developing JavaScript web controls I often test them by simply opening a file from hard drive. With the enhanced security DojoToolkit doesn't work locally since it uses XMLHTTP to load packages.

I know only one way around this - disable native XMLHTTP support in IE options. This forces DojoToolkit to use old ActiveX MSXML object.

Another problem is with Sider. It hosts WebBrowser control to show document with HTML views. All files are on the hard drive and native XMLHTTP refuses to load them. This made the application pretty much unusable.

Again, the only solution I found was to disable native XMLHTTP and force script to use old ActiveX object. However, I can't force users to change IE options just for my application. Microsoft, fortunately, provided a way to customize them for a specific application and I can disable native XMLHTTP only for Sider.

To disable it for a specific program use this registry key:

I'm not too happy about having to disable new features only because there's no way to configure them. Native XMLHTTP is faster and I would like to have an option of testing it. It's not essential for me now, but at some point it might be more important. For now I can look for an alternative on the Internet from time to time, hoping that there will be a better solution to loading local files through XMLHTTP than simply disabling native XMLHTTP feature.