How do I put a number on my Google Chrome extension? [duplicate]

This question already has answers here: 开发者_Go百科 Closed 10 years ago.

Possible Duplicate:

Google Chrome Extension Numbers on the Icon

So I'm developing a chrome extension and I would like to put a number on the icon. I'm assuming this is done through the canvas element but I can't find any examples. Anyone have an example they want to share?

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The number is called a "badge", and you can use up to four characters: http://code.google.com/chrome/extensions/browserAction.html

Call setBadgeText() to change it.