Help with .change (show a field on a <select> change)

Help with .change (show a field on a <select> change)

First off, any help would be greatly appreciated. I'm sure some experts around here wouldn't have a problem at all! Below is the relative code:

  1. <select id="cash_or_check">
  2.       <option value="cash" SELECTED>Cash</option>
  3.       <option value="check">Check</option>
  4. </select>
  5. <input type="text" id="check_number" name="check_number" size="10" />

  1. $(document).ready(function(){
  2.       $('#check_number').hide();
  3. });
  4. $('#cash_or_check').change(function() {
  5.       $('#check_number').show();
  6. });

All I am attempting to do is when the value is changed from "cash" to "check" the text field "check_number" appears. As of right now I have it hidden via the first three lines of the JavaScript file, but the field doesn't appear when "cash_or_check" is selected.

Thanks!