title: jQuery validate invalidHandler with alert still submits in Firefox?
body: <p>Can't fathom this at all.
  Using validate jQuery (1.6.2) with validate plugin (1.8.1).
  Have the following invalidHandler code which works fine in all browsers if the submit button is clicked. 
  However, if the form is submit by hitting enter on the keyboard after filling any field in, in Firefox (versions 5 and 6 anyway), you get the alert about the number of errors but the form still submits anyway!
  The form is not submit in other browsers, and if the alert line is removed, it works fine in Firefox. But we need the alert, so if anyone has any ideas on how to fix this it would be <em>greatly</em> appreciated - I'm not used to things acting up just in Firefox! :)</p>
  
  <pre><code>invalidHandler: function(form, validator) {
             var errors = validator.numberOfInvalids();
             if (errors)
             {
                     var message = (errors == 1)
                       ? '1 field has an error. It has been highlighted'
                       : errors + ' fields have errors. They have been highlighted';
                       alert(message);
                       //return false;
             }
  </code></pre>
  
  <p>} </p>