Use only Element.scrollHeight to get the correct height of the iframe document. Fixes issues where body.offsetHeight is smaller than the content's CSS height.
Use only Element.scrollHeight to get the correct height of the iframe document. Fixes issues where body.offsetHeight is smaller than the content's CSS height.

https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/offsetHeight:
"For the document body object, the measurement includes total linear content height instead of the element's CSS height. Floated elements extending below other linear content are ignored."

mthieleguj/setIframeHeight,mthieleguj/setIframeHeight