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

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?

Community · Accepted Answer · 2017-05-23 12:17:52Z

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, 2017 at 12:17

CommunityBot

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answered Sep 27, 2015 at 12:23

T.J. Crowder

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6 Comments

T.J. Crowder Over a year ago

...although I can't immediately see any reason for preferring document.head over just using document.documentElement.

David Resnick Over a year ago

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...

T.J. Crowder Over a year ago

@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.

David Resnick Over a year ago

Yeah, I scratched my head looking at that... ;) Thanks a lot for your help!

T.J. Crowder Over a year ago

@Legends: On modern browsers today, yeah. Not on (say) IE11. I'm not even sure what support was like in 2015.

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