Jquery form validation - enforcing alphnumeric -

does know why validation not working, trying enforce alphnumeric input of 8-12 chars nothing happening, have linked external jquery form validation library can see:

<form id="usertest">       <table>    <tr>     <td>password</td><td><input type="password" id="pwd"></input></td>    </tr>  </table> </form> 

the jquery:

$(function(){     $("form#usertest").validate({          rules:{               pwd:{                    alphanumeric: true,                    minlength: 8,                    maxlength: 12                     }          }     }); }); 

http://jsfiddle.net/zcjav/

thanks,

alan.

you missing additional-methods.js file alpha-numeric rule added, might want add required validation

jquery(function ($) {     $("form#usertest").validate({         rules:{             pwd:{                 required: true,                 alphanumeric: true,                 minlength: 8,                 maxlength: 12                  }         }     }); }); 

demo: fiddle