If you’ve written any kind of validation on user input, like onkeypress then you’ll know that sometimes you want to throttle the amount of times your function runs. A good example of this is Ajax based username validation – you don’t want to hit the server on every key press, because most users will be able to write their name in around 1/10th o…

Javascript: detect finish typing keystroke

function throttle(fn, delay) {
  var timer = null;
  return function () {
    var context = this, args = arguments;
    clearTimeout(timer);
    timer = setTimeout(function () {
      fn.apply(context, args);
    }, delay);
  };
}


$('input.username').keypress(throttle(function (event) {
  // do the Ajax request
}, 250));