Adjust width and height of iframe to fit with content in it

Question

I need a solution for auto-adjusting the width and height of an iframe to barely fit its content. The point is that t

Answer 1

Clearly there are lots of scenarios, however, I had same domain for document and iframe and I was able to tack this on to the end of my iframe content:

var parentContainer = parent.document.querySelector("iframe[src*=\"" + window.location.pathname + "\"]");
parentContainer.style.height = document.body.scrollHeight + 50 + 'px';

This 'finds' the parent container and then sets the length adding on a fudge factor of 50 pixels to remove the scroll bar.

There is nothing there to 'observe' the document height changing, this I did not need for my use case. In my answer I do bring a means of referencing the parent container without using ids baked into the parent/iframe content.