can server timeout be controlled by code?

I have used a tutorial to create a PHP script to upload files to a server. It works beautifully for images and small files < 10mb but over that size it fails. I believe that this may be due to a server timeout. The question is, if I am correct in my assumption is there a way to tell the server to wait until the file has uploaded?

Of course there may be another issue I haven't thought of, according to the script I have the large uploads aren't producing an error and the "success" text is displayed!

Any helpful advice would be appreciated :)