Regular Expressions

Regular Expressions

I am trying to match a form field value to a regular expression, to validate an e-mail address on the client side. It doesn't work (I come from Prototype) and for the life of me, can't figure out why.
$('input#email').blur(function(){
   var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
   if($('input#email').val() == filter){
      $('span#email_good').show();
      $('span#email_odd').hide();
   } else{
      $('span#email_odd').show();
      $('span#email_good').hide();
   }
});