// the iframe of the div I need to access
var iframe = document.getElementsByTagName("iframe")[2];
var innerDoc = iframe.contentDocument || iframe.contentWindow.document;
// resize 'player' in the iframe
innerDoc.getElementById('player').width = "1000px";
innerDoc.getElementById('player').height = "650px";
Running in a userscript for this url: http://www.free-tv-video-online.me/player/sockshare.php?id=24DA6EAA2561FD60
Why does Chrome come out with this error and fail the script?:
Unsafe JavaScript attempt to access frame with URL http://www.sockshare.com/embed/24DA6EAA2561FD60
from frame with URL http://www.free-tv-video-online.me/player/sockshare.php?id=24DA6EAA2561FD60.
Domains, protocols and ports must match.
(I’m only a basic Javascript user)
Final code, many thanks to the answerer:
// ==UserScript==
// @name Resize
// @include http://www.free-tv-video-online.me/player/sockshare.php*
// @include http://www.sockshare.com/*
// ==/UserScript==
if (!(window.top === window.self)) {
var player = document.getElementById('player');
setSize(player);
}
function setSize(player) {
player.style.setProperty("width", "1000px");
player.style.setProperty("height", "650px");
}
It’s true that ordinary javascript cannot access iframe content, that’s on a different domain, for security reasons. However, this by no means stops userscripts in Chrome, Tampermonkey or Greasemonkey.
You can process iframed content in a userscript because Chrome (and Firefox) process iframe’d pages just as if they were the main page. Accounting for that, scripting such pages is a snap.
For example, suppose you have this page at domain_A.com:
If you set your
@matchdirectives like this:Then your script will run twice — once on the main page and once on the iframe as though it were a standalone page.
So if your script was like this:
You would see the main page in lime-green, and the iframed page in pink.
Alternatively, you can test like this:
As you discovered (per comment on another answer), you can disable the same origin policy on Chrome. Don’t do this! You will leave yourself open to all kinds of shenanigans set up by bad people. In addition to evil sites, many nominally “good” sites — that allow users to post content — could potentially track, hack, or spoof you.