The following summary block is embedded here as an iFrame which comes from a SquareSpace page (https://www.grcrane.com/new-page). One problem with iFrames is that the height must be defined large enough to fit the entire content, otherwise an additional inner scrollbar will be needed. I’ve added some extra code in the origin SquareSpace site, and the the embedded code so both sites can talk to each other and adjust the iFrame height as the content changes. Try expanding/contracting the iFrame content by clicking on the + and - buttons below to see what happens.

The original header and footer have been removed. Also, notice what happens if you click on one of the image links. The new page content, from the SquareSpace website will replace the summary block content, and automatically adjust to the appropriate height.