Take a look at the source. It uses an IE-proprietary something or other to mock the behavior. http://msdn.microsoft.com/en-us/library/ms531424%28v=VS.85%29.asp

Take a look at the source. It uses an IE-proprietary something or other to mock the behavior. http://msdn.microsoft.com/en-us/library/ms531424%28v=VS.85%29.aspx http://msdn.microsoft.com/en-us/library/ms531424%28v=VS.85%2... Been available since IE 5.5, apparently. Who knew?