Js Marquee has going out of where

[Mean]

I have a Js marquee. The codings of that is all true.
But when i put that in headinclude, it seems like very very long.

My marquee is this
http://www.forumistan.net/idndex.html
The long is 970 px.

And here is the same one in the forum.
http://www.forumistan.net/

My question is, why is that seems very very long in the forum ??

I tried to get that content by using iframe, but when i do that, forums are not showing etc.

<iframe src=http://www.forumistan.net/idndex.html height="27" width="970" border="0" cellspacing="0">