When you get the message "Object doesn't support this property or method", how do you find out what "Object" is?

To get at IE's debugging information, you have to enable script debugging:

1. In Internet Explorer, choose Internet Options from the Tools menu.
2. In the Internet Options dialog box, click the Advanced tab.
3. On the Advanced tab, under Browsing, clear Disable Script Debugging.
4. Click OK.

http://msdn.microsoft.com/en-us/library/ms241741%28v=vs.80%29.aspx

If you have IE 8 or above, you can use their developer tools to debug:

http://msdn.microsoft.com/en-us/library/dd565625%28v=vs.85%29.aspx