# Is run\_at page\_start in manifest.json really working?

**URL:** <https://discourse.mozilla.org/t/is-run-at-page-start-in-manifest-json-really-working/19432>\
**Category:** Development\
**Created:** [September 21, 2017, 9:11pm UTC](https://discourse.mozilla.org/t/is-run-at-page-start-in-manifest-json-really-working/19432 "2017-09-21T21:11:28Z")\
**Posts on this page:** 1\
**Page:** 2

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**Author:** ![NilkasG](https://avatars.discourse-cdn.com/v4/letter/n/0ea827/32.png) [@NilkasG](https://discourse.mozilla.org/u/NilkasG)\
**Post date:** [September 24, 2017, 5:14pm UTC](https://discourse.mozilla.org/t/is-run-at-page-start-in-manifest-json-really-working/19432/22 "2017-09-24T17:14:54Z")

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Literally none of your statements is true:

> sure it’s possible with jquery.

jQuery can’t attach capturing listeners. See e.g.:

> <https://stackoverflow.com/questions/24585698/capturing-and-bubbling-using-jquery/24585928#24585928>

> xray vision is concerning content and background script communication

Xray is a thin, in-process isolation layer:  
[https://developer.mozilla.org/en-US/docs/Mozilla/Tech/Xray\_vision](https://developer.mozilla.org/en-US/docs/Mozilla/Tech/Xray_vision)  
using it between content and background script wouldn’t even work because they live in different processes.

> it’s not inline scripting, and so on.

As far as CSP is concered, it is.

> i’m out of this conversation.

Well, suit yourself 🙂

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