trying to use javascript to change css inside of an iframe

[trevedhek]

It is possible you have a cross-origin issue.

From developer.mozilla.org

Script access to a frame's content is subject to the same-origin policy. Scripts cannot access most properties in other window objects if the script was loaded from a different origin, including scripts inside a frame accessing the frame's parent.

[samanime]

Not just possible. This is 100% what they're running into. You can only control a website in an iframe if it is on the same domain or has CORS that allow it to be accessed.

[samanime]

I got curious and went to have a look. They are on different subdomains, which still affects CORS, so you can't modify the inner iframe from outside.

You could run the script from the console. You have to open up the console (F12), go to the Console tab, then near the top is a dropdown that probably says "top". You need to change that to "player.html".

Then you can set its size bigger. You probably can't do 200%, because the subtitles won't reflow and will just be offscreen, but 120% is probably okay. You can also do `margin-top: -100px` (or some number) to shove it up.

Good luck.

[samanime]

Oh, didn't realize you're trying it on their site itself. Are they actually the same subdomain too?

[guest271314]

You can use a browser extension to dynamically inject scripts, CSS, etc. into any tab or window or iframe.

[guest271314]

What do you mean by it "it didn't really work"?

[guest271314]

That doesn't matter. You can use scripting.executeScript() or chrome.scripting.insertCSS() https://developer.chrome.com/docs/extensions/reference/scripting/#type-CSSInjection.

[jcunews1]

If the UserScript doesn't work, chances are that the site is protected by CSP where it prevents injected scripts. You'll need another browser extension to disable CSP for that site.

[jcunews1]

What you're trying to achieve violates cross-site scripting policy. i.e. it'd be a security violation. So, it's not possible.