As slashnick pointed out, you can use the “for in” construct to iterate over an object for its attribute names. However you’ll be iterating over all attribute names in the object’s prototype chain. If you want to iterate only over the object’s own attributes, you can make use of the Object#hasOwnProperty() method. Thus having the following.

for (var key in obj) {
if (obj.hasOwnProperty(key)) {
/* useful code here */
}
}

Wish I’d known of that a year ago.

Samuli Kaipiainen and Matti Paksula from the University of Helsinki Department of Computer Science wrote a great overview of SVG and Canvas performance issues. The above summarizes some of their thoughts specifically about the need for a scene graph, something I’ve wished for (esp. in regard to WebGL).

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And I’m not just putting this up because they referenced my post on SVG vs. Canvas. Really.