What's a simple way in Google Chrome to insert Javascript into sites?

I would like to be able to add custom snippets of javascript to any site that matches a regex. This is mostly because of sites that I use daily because of specialized content, but which have a poor design. I want to be able to do something like开发者_如何学运维:

• Visit site See that sidebar overwrites content
• Whip out developer tools, find div id for sidebar

• Edit a snippet of javascript which is executed on document.ready for this domain:

  $('#sidebar-right').remove();
  

A bit of searching for user scripts tells me that I need to be writing a Chrome extension, which seems unfortunate and overkill. Is there not an easier way, or an extension which is nothing but a javascript editor that assigns snippets to domains? I'd really like to be able to edit in Chrome itself, or at least have a file that I can just leave open in MacVim all the time. An extension requires unloading/installing to update as far as I can tell.

If I just had one big javascript file, that would be fine. I'd just wrap my customizations in domain checks.

Bonus love if I can write in CoffeeScript.

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The answer is to use the Tampermonkey chrome extension.

https://chrome.google.com/webstore/detail/dhdgffkkebhmkfjojejmpbldmpobfkfo

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Why not dotjs http://defunkt.io/dotjs/ ? It's local, you can version it with git, you can easily take it to another computer...

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Another alternative that neatly solves the problem is Custom JavaScript for websites. You just need to install the extension, which takes around 2 seconds, and then you can immediately start typing your custom JavaScript for the specified website.

The extension automatically recognizes the current website, so all you need to do is write your code and click on Save. You can also easily import jQuery or your external scripts for convenience.

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Custom JavaScript for Websites 2 is an alternative to Custom JavaScript for Websites, with some bug fixes and sync scripts across devices feature.

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Witchcraft is another Google Chrome extension for loading custom Javascript and CSS, and it is supposedly for more avanced users. The older dotjs project repository lists Witchcraft as its successor.

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Snippets are available directly in Chrome Devtools

https://developers.google.com/web/tools/chrome-devtools/javascript/snippets

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What you're looking for is Greasemonkey. But wait, Greasemonkey is for Firefox only, right? Turns out, you can install Greasemonkey user-scripts as native Chrome add-ons. Just go to userscripts.org and hit the Install button on one of them, and Chrome will automatically convert it into a native add-on. Then, write your own and install it using Chrome.

Note: This only works in Chrome 4.0.