Nicholas Zakas is a Javascript guru and principle front-end engineer for the Yahoo! homepage. Zakas just announced his new book High Performance JavaScript, which you should order today.

Zakas is pretty much the man when it comes to Javascript performance, and in June he gave a Google Tech Talk entitled Speed Up Your Javascript.

While Javascript optimization is by no means black-and-white, here’s a list of 10 tips from Nicholas’ talk that will help you write Javascript that really flies.

1. Define local variables

When a variable is referenced, Javascript hunts it down by looping through the different members of the scope chain. This scope chain is the set of variables available within the current scope, and across all major browsers it has at least two items: a set of local variables and a set of global variables.

Simply put, the deeper the engine has to dig into this … Read more…