Hide a number of pixels (height) of the content in an iframe using jquery?

Hide a number of pixels (height) of the content in an iframe using jquery?

Hi,
Im making a website in which I want to "embed" another website (not mine) - simplesignup.se - through which i've created an event. The problem is that I want to hide the footer of that page, maybe the header to if its possible, but since the height of the other page varies throughout the steps in the "buying-process" I can't set a fixed height...

Is it possible to fix this problem using jquery and how do I do that?

So, something like this is what i want: autoheight - x pixels from the top - x pixels from the bottom

I hope it all made sense to you, please excuse for my english.. :)

/ Ingrid