I wonder what kind of valuable information you expect to get from this function.
But whatever it is, please be advised that it is considered bad practice, because you are essentially practicing server based client sniffing, and the only base of information is the user agent string, which can be anything and does not need to represent the real situation. Also, information like "javascript" can only represent the coded ability of the client, not the current configured abilities, which can be less.
If you still think the function to be of any use, you have to solve the task of getting a copy of that "browscap.ini" file this function wants to use, and you have to constantly update this file to include new browser versions.
There is a link to a file source on the documentation page of get_browser()
. Download a file and point the INI setting to that location. Make sure to activate it by removing the semikolon.