QuerySelector for Web Elements Inside iframe

Edit: New title. What I'm looking for is a document.querySelector for elements inside an iframe.

I've done quite a bit of Googling for an answer and finally I'm stumped.

I'm trying to query inside an iframe. I'm building string selectors to be used in Selenium and usually I just inspect the element with Firebug, and use document.querySelectorAll("theStringIBuid");

But it doesn't work with elements inside iframes. I've tried all of the below to get an element "radiobutton1" inside the "page-iframe" iframe.

var elem1 = ".page-iframe";
console.log(elem1);
var elem2 = ".radiobutton1";
console.log(elem2);
document.querySelectorAll(elem1+elem2+"");

document.querySelectorAll('.page-iframe').contentWindow.document.body.querySelectorAll('.radiobutton1')
document.getElementById('.page-iframe').contentWindow.document.body.innerHTML;

[].forEach.call( document.querySelectorAll('.page-iframe'), 
function  fn(elem){ 
console.log(elem.contentWindow.document.body.querySelectorAll('.radiobutton1')); });

var contentWindow = document.getElementById('.page-iframe').contentWindow 
var contentWindow = document.querySelectorAll('.page-iframe') 
var contentWindow = document.querySelectorAll('.page-iframe')[0].contentWindow

Thanks-

Solution 1:

simple es6 adapted from h3manth:

document.querySelectorAll('iframe').forEach( item =>
    console.log(item.contentWindow.document.body.querySelectorAll('a'))
)

Solution 2:

if the original page's url isn't at the same domain with the iframe content, the javascript will treat the iframe as a black box, meaning it will not see anything inside it.

Solution 3:

You can do this: document.querySelector("iframe").contentWindow.document.querySelector("button") https://m.youtube.com/watch?v=-mNp3-UX9Qc