caching-array-lengths-for-loop.js
var arr = new Array(1000),
len, i;
for (i = 0; i < arr.length; i++) {
// Bad - size needs to be recalculated 1000 times
}
for (i = 0, len = arr.length; i < len; i++) {
// Good - size is calculated only 1 time and then stored
}