What I am trying to make this script do is a user adds in a ID and it will execute that the URL with the user input. So for the user puts in, 123 the excuted URL is http://XXXXXXXXXXXXXXXX.com?u=123

method="get" plus a text box called "u"

I suck with HTML so I don't understand how to do that.

<form method="get" ...>
<input type="text" name="u" />
</form>