JSFiddle - React, Tailwind, and code Playground

HTML

<iframe width="400" height="100%" src="http://www.google.com.br"  onLoad="calcHeight();" frameborder="1" id="resize" name="resize"></iframe>

JavaScript

function calcHeight()

{

  //find the height of the internal page

  var the_height=

    document.getElementById('resize').contentWindow.

      document.body.scrollHeight;

 

  //change the height of the iframe

  document.getElementById('resize').height=

      the_height;

}