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Javascript (apparently) successfully blocked by NoScript - but why is the console completely empty although it should report that scripts failed to load?

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  • Last reply by spider82

spider82
spider82
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Hi everybody,

hope you can help me understanding this.

Browser version: Firefox 60.9.0ESR, installed plugins: NoScript, Ublock Origin, HTTPS Everywhere

I'm using NoScript to block all Javascript by default and sometimes I want to verify that blocking works by looking at the console (F12) output.

Normally, when I visit a website and NoScript blocks all Javascript ressources, the console (F12) should show me error messages that scripts failed to load.

However, on some sites (e.g. stackoverflow.com), when I open the console it is completely empty (no output at all) - although Javascript apparently has been blocked (NoScript tells me that it has blocked all scripts and stackoverflow.com displays that "stackoverflow is best viewed with Javascript enabled").

Interestingly, when I leave the console open and refresh that page, all the expected error messages about failed scripts are suddenly displayed in the console.

So my questions are: 1) what could be the reason that the expected error messages are only displayed when I refresh the page? 2) could this mean that at the time the console is empty, some scripts are executed? Although NoScript tells me it has blocked all of them and the main site apparently was loaded without Javascript?

Your help would be appreciated. Thanks

Hi everybody, hope you can help me understanding this. Browser version: Firefox 60.9.0ESR, installed plugins: NoScript, Ublock Origin, HTTPS Everywhere I'm using NoScript to block all Javascript by default and sometimes I want to verify that blocking works by looking at the console (F12) output. Normally, when I visit a website and NoScript blocks all Javascript ressources, the console (F12) should show me error messages that scripts failed to load. However, on some sites (e.g. stackoverflow.com), when I open the console it is completely empty (no output at all) - although Javascript apparently has been blocked (NoScript tells me that it has blocked all scripts and stackoverflow.com displays that "stackoverflow is best viewed with Javascript enabled"). Interestingly, when I leave the console open and refresh that page, all the expected error messages about failed scripts are suddenly displayed in the console. So my questions are: 1) what could be the reason that the expected error messages are only displayed when I refresh the page? 2) could this mean that at the time the console is empty, some scripts are executed? Although NoScript tells me it has blocked all of them and the main site apparently was loaded without Javascript? Your help would be appreciated. Thanks

All Replies (2)

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
  • Top 10 Contributor
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spider82 said

Interestingly, when I leave the console open and refresh that page, all the expected error messages about failed scripts are suddenly displayed in the console.

So my questions are:
  1. what could be the reason that the expected error messages are only displayed when I refresh the page?
  2. could this mean that at the time the console is empty, some scripts are executed? Although NoScript tells me it has blocked all of them and the main site apparently was loaded without Javascript?

I use NoScript, but I almost never look in the console, so I'm not sure if I've ever seen that myself.

I suspect it could be due to Firefox restoring the page from cache, and if the scripts were blocked before, then they wouldn't be there to trigger a block, or maybe NoScript isn't triggered when a page is reloaded from cache (??).

If you don't get a satisfactory reply here (ahem), you could consider asking on the NoScript forum over here: https://forums.informaction.com/viewforum.php?f=3

spider82
spider82 Question owner
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Thank you for your answer.

When I experienced this for the first time, the cache was definitely empty.

However, I can't say for sure that the other times this was the case, too.

Maybe there are several possible reasons for this behavior and one could be that the page is restored from cache.

Thanks also for the tip with the NoScript forum, I think I will wait a bit if this thread brings more answers.