it\'s not working.i mean i have many scripts to get ip and os but anyway get_browser is internal function and should work but its not.when i try to get a print_r on the func
Make sure you have an up-to-date browscap file. Read the notes in the documentation of get_browser.
If you're not a server administrator, check out phpbrowcap which implements the same functionality but makes it possible for you to use another broswcap file than the server-wide one.