How do I publish a Greasemonkey script as a Firefox add-on?

Question

I recently have worked on a script in Greasemonkey and would like to publish it as an add-on for Firefox. What is the easiest way to do this?

Answer 1

While you can "compile" a GreaseMonkey script (see Brock's answer), this solution isn't exactly well-supported. The more reliable option would be using the Add-on SDK and JPM. Your lib/main.js file can be really simple (page-mod module documentation):

var data = require("sdk/self").data;
var pageMod = require("sdk/page-mod");
pageMod.PageMod({
  include: "*.example.com",
  contentScriptWhen: 'end',
  contentScriptFile: data.url("contentScript.js")
});

This is equivalent to the following GreaseMonkey script header:

// @include http://example.com/*
// @include http://*.example.com/*

And then you add your GreaseMonkey script as data/contentScript.js (Add-on SDK will ignore the GreaseMonkey header, the info is specified elsewhere) and build the extension. In most cases it will just work - unless your GreaseMonkey script uses any special GreaseMonkey API of course, in which case you will need to find a replacement. unsafeWindow is supported by the way (usual warnings apply).

Answer 2

Just post your script at userscripts.org¹OpenUserJS.org (Or one of the other userscripts.org replacements).
Trying to repackage it as an add-on is usually more trouble than it is worth.

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If you really must, you can use the Greasemonkey script compiler to turn your script into an "add-on", and then submit that add-on to Mozilla, via the normal add-on process.

Note that Wladimir's answer is better than the Greasemonkey script compiler.

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¹Userscripts.org is now long dead.