JQuery Examine First Character in Text Field as its typed
<p>I've a simple html form with text field with id="zip" what I want to do is monitor that field and whenever the value changes enable/disable an array of checkboxes based on the input. Currently the change event only fires once I tab or the zip input field. I tried experimenting with keypress but it would always give the value of the text field minus the current character:</p>

<pre><code> &lt;form id+"testform"&gt;
 Zip Code &lt;input id="zip" value="" /&gt;&lt;br /&gt;
 Zip 4&lt;input type="checkbox" id="check_one" /&gt;&lt;br /&gt;

 Zip 3&lt;input type="checkbox" id="check_two" /&gt;&lt;br /&gt;
&lt;/form&gt;

&lt;script type="text/javascript" src="http://code.jquery.com/jquery-1.4.4.min.js"&gt;&lt;/script&gt;


&lt;script type="text/javascript"&gt;
 $('#zip').change(function() {
 var zipCode = $(this).val();
 zipCode = zipCode.substring(0,1);



 if(zipCode == 3) {
  $("#check_one").attr('disabled','disabled');
    $("#check_two").removeAttr('disabled');


 } else if (zipCode == 4) {
  $("#check_one").removeAttr('disabled');
    $("#check_two").attr('disabled','disabled');


 } else {
  $("#check_one").removeAttr('disabled');
  $("#check_two").removeAttr('disabled');

 }
});
&lt;/script&gt;
</code></pre>

<p>Is there an appropriate jQuery event that fires after each character is input?</p>
