jQuery textbox change event doesn't fire until textbox loses focus?

Question

Binding to both events is the typical way to do it. You can also bind to the paste event.

You can bind to multiple events like this:

$("#textbox").on('change keyup paste', function() {
    console.log('I am pretty sure the text box changed');
});

If you wanted to be pedantic about it, you should also bind to mouseup to cater for dragging text around, and add a lastValue variable to ensure that the text actually did change:

var lastValue = '';
$("#textbox").on('change keyup paste mouseup', function() {
    if ($(this).val() != lastValue) {
        lastValue = $(this).val();
        console.log('The text box really changed this time');
    }
});

And if you want to be super duper pedantic then you should use an interval timer to cater for auto fill, plugins, etc:

var lastValue = '';
setInterval(function() {
    if ($("#textbox").val() != lastValue) {
        lastValue = $("#textbox").val();
        console.log('I am definitely sure the text box realy realy changed this time');
    }
}, 500);

On modern browsers, you can use the input event:

DEMO

$("#textbox").on('input',function() {alert("Change detected!");});

$(this).bind('input propertychange', function() {
        //your code here
    });

This is works for typing, paste, right click mouse paste etc.

if you write anything in your textbox, the event gets fired.
code as follows :

HTML:

<input type="text" id="textbox" />

JS:

<script type="text/javascript">
  $(function () {
      $("#textbox").bind('input', function() {
      alert("letter entered");
      });
   });
</script>

Try this:

$("#textbox").bind('paste',function() {alert("Change detected!");});

See demo on JSFiddle.