How exactly can I replace an iframe with a div and Javascript?

Question

I have a page that loads an external HTML page into an iFrame. There are two problems I am facing with this:

1. The iFrame is always a fixed height, but I want it

Answer 1

#mydiv {
      all: initial; /* blocking inheritance for all properties */
}

from How To Isolate a div from public CSS styles?

This solution saved my day.