如何防止browser_action每次重新加载其弹出窗口？

Question

I'm developing a webextension and I'm stuck with following problem.

I have browser_action that displays popup window with some content. The problem is, it takes 3-4 seconds to load, and user has to wait every time he opens this browser action.

I want somehow force browser_action to load DOM of popup window just once , so when I open this action again it shows me already rendered window.

I can't preload any assets through background script, because the asset is <iframe> of remote website and you can't easily store rendered DOM in localStorage just to display it later on user request.

I thought about putting <iframe> inside background script and displaying it somehow in browser_action popup window, but I failed to find out how to do that.

Background page is loaded once and stays forever while extension is enabled, so maybe I could display it contents inside browser_action popup window somehow?

Answer 1

Unfortunately, I don't think that's not possible. Your best bet would be to show some useful UI while the iframe loads.

It's certainly not possible to make the popup page itself be persistent.

And I'm 98% positive you can't swap in a loaded tab/frame into the page of the popup. Chrome does it internally sometimes (preload then swap, see tabs.onReplaced ), but you have little control over this mechanism.

It seems you can trigger it with preload links :

<link rel="preload" href="https://example.com/"
      as="document" crossorigin="anonymous">

However, it serves little purpose to embed that into the popup page (it will be fetched when the popup loads, which is milliseconds of difference) and I'm reasonably sure that preloading it from, say, the background page won't carry over to the popup, despite them normally sharing the browser process. You can experiment though!