Compatibility Issues

Some developers might be concerned that their ASP.NET 2.0 application controls won't work as anticipated due to changes in IE7. I didn't find any problems in this area, as long as you configure the control properly. Even the FileUpload control works as anticipated. The only requirement is that you sent IE7 to allow for scripts. Interestingly enough, ASP.NET 2.0 turns controls into a combination of JavaScript and HTML that appears to work fine with IE7.

A check of the request header information that IE7 provides shows that some applications will break when they employ poor range-checking methods. My test system shows that IE7 supports nine file types by default: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, and */*. The user agent information is also different: Mozilla/4.0 (compatible), MSIE 7.0, Windows NT 5.1, SV1, .NET CLR 1.1.4322, and .NET CLR 2.0.50727. If your application checks for specific version numbers, rather than a range of numbers, it may stop working with IE7. However, it's actually good that Microsoft has changed the user information appropriately, because you can use it to detect potential client problems before they become an issue for the user.

I tested a number of pop-up types. All forms of pop-up work just fine in the Intranet zone, but they usually fail in the Internet zone. You can change this functionality by using the Security tab of the Options dialog box, just as you already have. The difference is that the default settings are more aggressive. Unlike previous versions, IE7 defaults to blocking most pop-ups.

In addition, IE7 is more aggressive about cookies. Make sure your Web site includes a privacy policy to ensure you can continue using cookies.

User Issues

IE7 has one new feature that has the potential to create nothing but problems. The "Fix My Settings" feature is a good idea... in theory. Whenever a user makes a settings change that could possibly cause problems, IE7 keeps reminding him about it. A single click is all it takes to change the settings back to a safe state.

That sounds good, but it will very likely cause problems for your application. You know that the user is going to click "Fix My Settings" at some point. I can see this particular feature generating a lot of support calls. You'll need to develop your applications so that they fail gracefully and send a request to the administrator to check the user's settings. That way, when your application does require settings that "Fix My Settings" modifies, you can at least help the user to get the application back to a workable state.

Another new feature that could cause problems is the "Delete Browsing History" feature on the Tools menu. Users who are used to working with the older versions of IE will find that this option deletes everything, rather than an individual component. If your application relies on permanent cookies, it may no longer work as anticipated.

Users selecting "Delete Browsing History" will remove the permanent cookies on their system, and create problems for any application features that rely on those cookies. Of course, there's always the other side of this coin; users who rely on this feature while working in a public venue or on a friend's machine are far less likely to leave crumbs around that someone could exploit. Overall, this is a good feature and you should welcome it, but be aware of the possible side effects.