FireFox Extension for Cacher, the code snippet organizer
Since FF does NOT support most scripting (AppleScript, JavaScript in Browser), I thought I'd post the above link to a FF Extension that allows you to grab a code block on a web page in FF, and save it to Cacher code snippet organizer . Cacher offers a limited free version as well as more extensive paid versions.
I used Cacher (and its predecessor GistBox) for about a year, and found it to be a good snippet manager, although not my favorite. One of its strong points is that it syncs with GitHub Gists.
I have had very limited experience with this FF Extension, so I can't recommend it one way or the other, but it might provide a decent tool to quickly get code on a FF page. You can also save any selected text using the Cacher context menu. Select a the text, then: Right-click -> Cacher -> Save Selection as Snippet