Iframe 100% height (FIXED) - no show header and footer


I am using iframe as:

If I use “position: fixed” there is no Header and Footer but the Iframe works correctly.

The problem I want to keep at 100% variable height and includes the Header and Footer - and thats not work.

How i can to use a similar function of “Fixed” height but the header and the footer will not disappear?

Please provide a share link of your project so we can see what you are referring to as “the footer and header not disappear?”