css - Set iframe height in pixels -

I want to display a top bar with a height of 72px height of my page and then load an iframe below Which fills the full page (topbar height height).

Before I can start taking my top-bar too ... Somehow my IFrame sets any height attribute for it:

  Width = '100%' height = '1200' style = 'overflow: hidden; Height: 100%; Width: 100% 'or width =' 100% 'height =' 100% 'style =' overflow: hidden; Height: 100%, Width: 100% ' 

I am reading this post:

But do not have any luck here:

height: 100% style , which is already deleted, now iframe Height should be 1200px.