WWW::selenium moudle function get_all_window_names return undef

Hi : I have a testing project UI, and now click a hyperlink pop up new window ,so I want to operate the pop up window,I want to get the IE browser window's names or ids.But I use WWW:: selenium's function named get_all_window_names or get_all_window_ids ,they return array is null ,so I don't

I can't understand this function that what are parameters ,can you help me?

Hi all : I watch a function that is package "Test::More " ,which is that segment such as : sub ok ($;$) { } and sub is ($$;$) { } please tell me what means "($;$)" , or give me some reference manual let me know it; thank you! 2011-01-05 Best Regards! -Yang