>>Can you debug it?
>
>I had to move it up to the higher frame. The onload of an inside frame does not work well with the onload. There is a dependency from the master frame. Once I moved the code to the master frame, it works.

I had the same problem with the .ScrollHeight (in IE only, but then IE was what about half of the users had) when I was implementing an autoexpanding textarea plugin. It seems that it stays at zero until something else happens. My guess is that the property isn't filled until the control is actually rendered.