How to invoke javascript function on web page from chrome extension?

Question

There is a web site with this snippet in every page:

var refreshSite; 
refreshSiteInterval();
function refreshSiteInterval() {
  refreshSite = setInterval(
    function() { document.location = document.location; }, 
    420000);
};
function stopRefreshSite() {
  clearInterval(refreshSite);
}

Calling stopRefreshSite() from javascript console stops the timed refresh from occurring.

I'd like to disable this recurring refresh with a chrome extension. I thought that a content script which calls stopRefreshSite() whenever the page loads makes sense, though because content scripts execute in an isolated world this doesn't seem to be possible.

Is there any way to call the webpage function? Or would trying to prevent the original javascript from running in the first place be a better strategy?

score 4 · Accepted Answer · edited May 23 '17 at 12:17

4

To execute script on the page, you have to insert a script element into it, which is easily done and covered in this answer: Building a Chrome Extension - Inject code in a page using a Content script.

In your case:

var script = document.createElement('script');
script.textContent = "stopRefreshSite()";
(document.head||document.documentElement).appendChild(script);
script.parentNode.removeChild(script);

edited May 23 '17 at 12:17

Community

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answered Sep 27 '15 at 12:23

T.J. Crowder

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...although I can't immediately see any reason for preferring `document.head` over just using `document.documentElement`. – T.J. Crowder Sep 27 '15 at 12:37
I've added the script with "run_at": "document_end" and while the script is definitely running, I can't find the injected script element. I'm starting to debug... – David Resnick Sep 27 '15 at 13:11
@DavidResnick: Note the last line of the above. :-) We're removing it after adding it, since it's adding it that runs the code it contains. You could take that line out if you like. – T.J. Crowder Sep 27 '15 at 13:24
Yeah, I scratched my head looking at that... ;) Thanks a lot for your help! – David Resnick Sep 28 '15 at 07:33
`script.remove()` – Legends Feb 09 '18 at 17:01
1

@Legends: On *modern* browsers *today*, yeah. Not on (say) IE11. I'm not even sure what support was like in 2015. – T.J. Crowder Feb 09 '18 at 18:03

How to invoke javascript function on web page from chrome extension?

1 Answers1