Custom Site JS - Chrome Web Store
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Run your own (per url or domain) custom JavaScript on sites.

Have you ever wished you could customize a website to your personal preferences every time you visited it? Ever heard of a bookmarklet? Bookmarklets run JavaScript on a page for you when you click on the bookmark. But how inconvenient to have to click a bookmark every time you visit a site? What if you could have your JavaScript simply run on the site as the page loads with no extra effort from you? That's what this extension is about. Custom Site JS allows you to Add, Edit, or Delete snippets of custom JavaScript, that will automatically be run on a page for you based on a URL you provide. You can create as many as you like. The only limit is a maximum of 5 megabytes as the scripts are stored in your local storage. Everything is stored and run locally. This extension will never make any kind of external web request, network requests, or in short send any of your information anywhere. The only way it will pass any information outside of your local environment is if you create a snippet of JavaScript that explicitly sends information somewhere.

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ZedroidMar 1, 2024

now i can auto expand self text posts on reddit instead of clicking on a bookmarklet. So, i can hide the bookmark toolbar now. Make sure scroll to right in addon textbox to check "Enable on".


  • Version
  • Updated
    November 19, 2020
  • Offered by
    David Hicken
  • Size
  • Languages
    English (United States)
  • Developer
  • Non-trader
    This developer has not identified itself as a trader. For consumers in the European Union, please note that consumer rights do not apply to contracts between you and this developer.


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  • Not being used or transferred for purposes that are unrelated to the item's core functionality
  • Not being used or transferred to determine creditworthiness or for lending purposes


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