Ip log for security purposes???

How can I log someones IP using Javascript......you see I have a sub forum provided by Proboards. recently lots of these forums have been hacked. I thought that if onload of each page of the forum if the user was admin, which is me, and if the ip was the one that I embedd in the code or my own detected, than the user, who is me, can proceed as the admin, otherwise the window will just keep on closing....I like the idea but Im not sure if its possible since I dont know how to log the users ip and keep in the cookie...can anyone help plz

Javascript is for the CLIENT SIDE. That is, it has nothing to do with the server. You need a server-side langauge to properly accomplish your task. PHP, ASP, etc are what you are after. When a user requests a page, they send a bunch of information about themselves, such as: the browser they're using, their IP address, the OS, etc. You can grab that IP address very simply using a server-side language, and store it in a DB. There would be no point storing a user IP as a cookie on their machine. Also, using JS as a security measure is not feasible, as all you need to do to get around it is turn it off.