how to call a function on textchange in textfield using java script

just add change to the function that it works for both keydown and change:

$(function() {

var input = $('.input'),
    bar = $('.bar'),
    bw = bar.width(),
    percent = bar.find('.percent'),
    ps = percent.find('span');

input.on('keydown change', function(e) { // in here it works for both keydown and change
    if (e.keyCode == 13) {
        var t = $(this),
            val = t.val();
        if (val >= 0 && val <= 100) {
            var w = 100 - val,
                pw = (bw * w) / 100,
                pa = {
                    height: w + '%'
                },
                cw = (bw - pw) / 2,
                ca = {
                    left: cw
                }
            ps.animate(pa);
            cs.text(val + '%');
            circle.animate(ca, function () {
                circle.removeClass(name)
            }).addClass(name);
        } else {
            alert('range: 0 - 100');
            t.val('');
        }
    }
});

use keyup instead of keydown

 input.on('keyup', function(e) {
   ....

you can use onkeypress event like this :

HTML

   <div class="text">
   <input type="text" class="input"  value="0" onkeypress="return runScript(event)"   id="sliderValue170h"/>
   </div>

Javascript

 function runScript(e)
 {
     //Set Your logic
      if (e.keyCode == 13) {

      }
 }

$('#sliderValue170h').change(function(){
{
  //your code here
});

$('#sliderValue170h').bind('change keyup',function(){

var t = $(this),
            val = t.val();
        if (val >= 0 && val <= 100) {
            var w = 100 - val,
                pw = (bw * w) / 100,
                pa = {
                    height: w + '%'
                },
                cw = (bw - pw) / 2,
                ca = {
                    left: cw
                }
            ps.animate(pa);
            cs.text(val + '%');
            circle.animate(ca, function () {
                circle.removeClass(name)
            }).addClass(name);
        } else {
            alert('range: 0 - 100');
            t.val('');
        }
});