where can I learn about how do developer browser bookmarklets (language, framework, IDE, techniques etc)?

where can I learn about how do developer browser bookmarklets (language, framework, IDE, techniques etc)? Perhaps they are more of a Javascript development thing?

To give examples of what I'm talking about 开发者_如何学JAVAsee:

http://www.evernote.com/about/download/web_clipper.php

and

http://readitlaterlist.com/bookmarklets/

Thanks

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http://www.webreference.com/js/column35/ ?