HTML

<div class="seachbox">
    <input type="text" name="seach-text" id="seach-text">
</div>

Javascript:

function delay(callback, ms) {
  var timer = 0;
  return function () {
    var context = this,
      args = arguments;
    clearTimeout(timer);
    timer = setTimeout(function () {
      callback.apply(context, args);
    }, ms || 0);
  };
}

$('#seach-text').keyup(
  delay(function (e) {
    console.log('Time elapsed!', this.value);
  }, 500)
);