How to change width/height of iframe with document.getElementByid in javascript?

Question

I tried using document.getElementById("frame-id") , but it seems buggy. Mostly it returns undefined or null but sometimes it returns the iframe only for the first time it is called then again it starts returning undefined . Also I am unable to change or get style properties with document.getElementById("frame-id").style.width . Eg here is the fiddle https://jsfiddle.net/Lfq2u2o1/1/ You can check with the console.

Why are iframe elements not accesible with document.getElementByid or document.getElementsByClassName in javascript?

Answer 1

They are. You can't do anything inside the iframe with javascript (with the exception of window.postMessage()) but element selection works like any other selector in javascript.

Adding

console.log(document.getElementById("frame-id"));

to your fiddle should work perfectly.