Ask HN: In what order do browser addons process a webpage?

16 points by unethical_ban 9y ago ↗ HN

Say I have uMatrix, Ghostery and Privacy Badger, all operating on a site. What determines the order by which they alter a page?

4 comments

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benologist 9y ago ↗

You could make some very basic extensions, put in some console.logs and find out, but I think it would have to be the order they're installed or random so you can't exploit extensions up or downstream.

pvg 9y ago ↗

You might have better luck with this on SO but there's no guaranteed order (nor would it make much sense for there to be one)

silvaben 9y ago ↗

There is no specific order. I believe that it is randomized.

c0nducktr 9y ago ↗

From the nsIContentPolicy Firefox documentation[1]:

Note: The order of content policies in the above case depends on the precedence of installation.

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I recall reading somewhere that chromium used the reverse order, but I'm not certain this is still the case.

[1] https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/...