Website scripting addon different browser links here

In Chrome https://chrome.google.com/webstore/detail/website-scripting/aggnfbkmhedkekjoplldenefbchaoiln

In Firefox https://addons.mozilla.org/en-US/firefox/addon/website-scripting/

In Microsoft Edge https://microsoftedge.microsoft.com/addons/detail/lcofajjkcgijgdijbllafnjfnffilnmc

Extension description

Following list of functionalities available.

1. Insert javascript codes in web pages.
2. Can customize URL by using regular expressions.
3. Multiple scripts can be execute in same page.
4. Jquery support available.
5. This extension is completely open source.
6. To share your javascript code to public, there is push request link you can use it. We will review it and add to public usage.
7. When you need assistance for writing codes for your website we have request option to assist.
8. We open to contribution by developers for enhance the project.
9. You do have templates in the code, those are mostly reusable only.
10. By default some javascript codes will be provided. You can enable it, if it is relevant to you. Due to privacy we don't enable any scripts on default. You can read the javascript codes and activate it.

It also refers as web override or webpage overrides.