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Proposal: RegisteredContentScript.tabIds and RegisteredContentScript.excludeTabIds properties to filter injection #539
Description
(As discussed in #103)
Use Case
Some time-critical features can be provided only by document_start registered content scripts which run before any page script has a chance to: scripting.executeScript() is useless for this, bacause it doesn't provide reliable time guarantees.
However users may want to turn such features on/off on certain tabs only, e.g. in order to be sure a multi-site workflow like an e-commerce check-out/payment one are not disrupted by the extension. That's the case of the Disable all restrictions for this tab NoScript command, for instance.
Proposal
The above use case would be served if script registration could be filtered by tabId.
Therefore, in addition to the RegisteredContentScript properties already specified, we propose to add:
-
tabIdsOptional
anarrayofnumber. If defined, limits the injection to the tabs whose IDs are included in the array, after all the other requirements are met. If defined as an empty array, no injection will occur1 . IfpersistAcrossSessionsistrueor undefined, a "TypeError: tabIds can't be defined for persistent content scripts." exception will be thrown (in other words,persistAcrossSessionsMUST be set tofalse). -
excludeTabIdsOptional
anarrayofnumber. Tabs whose IDs are contained in this array will be excluded from injection, even if all the other requirements are met. This property won't be persisted even ifpersistAcrossSessionistrueor undefined, i.e. the registered content script will survive across sessions restarts and updates but, after those, will be injected in every tab and if retrieved viascripting.getRegisteredContentScripts()will haveexcludeTabIdsundefined. 2
If any of these two parametersThis filter could only be specified for non-persistent script registration, and would throw TypeError otherwise)
Footnotes
-
even if this might seem just a fancy expensive way to disable the
RegisteredContentScript, it can be argued that it's the least surprising and most consistent API. Alternatively, passing an empty array could throw as an invalid type. The worst, to be avoided at all costs to prevent bugs, would be an emptytabIdsarray falling back to match any tab. ↩ -
the different behavior regarding persistence between
tabIdsandexcludeTabIdsprovides a reliable mechanism to both turn off persistent features and add temporary features on certain tabs only. ↩
Activity
hackademix commentedon Feb 29, 2024
Better clarified the use case and proposed behavior regarding persistence in the main issue description, as a follow up of today's meeting discussion.
oliverdunk commentedon Apr 18, 2024
Hey @hackademix, thanks for opening this issue! I think you mentioned you had some workarounds for this in MV2 - would you be able to share what those are and how well they work?
We discussed this a bit on the Chrome side. We have no concerns about the capability, but are also concerned that this doesn't feel like the right sort of thing to be adding to this API. A better solution seems like being able to set global and per-tab parameters for content scripts, that you could then access synchronously from inside them. This is something we've discussed in the past and would still like to look at in the future.
Going to remove our follow-up label for now but definitely open to continuing the conversation.
hackademix commentedon Apr 18, 2024
Hey @oliverdunk, thank you for looking into this.
I believe the work-around you might have heard me alluding to is (https://github.com/hackademix/nscl/blob/main/service/DocStartInjection.js]this DocStartInjection NSCL module), which I don't think easily translates to the MV3 world because:
browser.contentScripts.register()on Firefox andbrowser.tab.executeScript()on Chromium, carefully timed and/or brute forced from bothwebNavigationandwebRequestlisteners.file:///URLsTherefore I really hope you reconsider the
opposed:chromelabel you've just attached to this issue, or otherwise finally act ASAP on your parametrized content scripts proposal, because we've been talking about this for more than 3 years now but for some reason we're still stuck here. Thanks again!dotproto commentedon Apr 8, 2026
2026 London F2F Triage
Consensus view as that it doesn't make sense to use tabIds as a primitive for modifying content scripts. Recognize that there's utility in addressing the use case of disabling an extension on a given tab, but don't think this is the right approach to do so.
See also #793