unnecessarily .lengthy problem

*sigh*



Ten years I've been writing code in this language. You'd think mistakes like this would not happen:

var arr = ["I", "forgot", ".length", "in", "the", "for", "loop"];


for (var i = 0; i < arr; i++) {
  //for some strange reason, nothing happens...
  alert("This will never alert, you moron!");
}

At the very least you'd hope it would only take a few minutes to figure out, not *ahem* two hours.