One thing I've learned from jsPerf is that this sort of micro-tuning tends to be particularly fruitless in JavaScript. Even if a tweak increases speed consisten

One thing I've learned from jsPerf is that this sort of micro-tuning tends to be particularly fruitless in JavaScript. Even if a tweak increases speed consistently across the target browsers, there's no telling which will optimize what cases in the next few versions. Basic things like caching DOM lookups are always good, but not so much the little things.