Dynamically change an iframes height

Hi!

I am having trouble with an HTML input.

How can I dynamically change an iframes height?

https://preview.webflow.com/preview/ashfishman?utm_medium=preview_link&utm_source=designer&utm_content=ashfishman&preview=73b2750bc165695e65d946800356319d&pageId=642c9a44c77dbb862a82d8b2&workflow=preview

hi! can anyone help? I want the HTML to only “expand” when an action is done. otherwise i do not want a white blank space to be there.

Please help!!

What research you have done on your own on internet?