debounce.js

function makeDebounce(real, interval) {
  var timerValue;
  return function() {
    if (timerValue) {
      clearTimer(timerValue)
    }
    timerValue = setTimer(real, interval)
  }
}

function myRealFunction() {
  // ...
}

foo.onchange = makeDebounce(myRealFunction, 1000);