There are times when we need to make sure that our code not only works with IE, but also with other popular web browsers, such as FireFox.
Here are the steps to do this:
1. Right click the aspx page;
2. Select "browser with" option;
3. In the pop up dialog box, select "add" to add a broswer. Find and point to firefox.exe
4. Click the "Set as Default" button.