On: Always return on events is faster, but why?

[Stratoscope]

The two functions are different, but their return values are identical. The === is comparing the return values.

Consider this example:

  function onePlusOne() { return 1 + 1; }
  function two() { return 2; }

  alert( onePlusOne === two );  // false, not the same function
  alert( onePlusOne() === two() );  // true, same value