title: Bootstrap 3 Signin form and jQuery validation plugin
body: <p>I use Bootstrap 3 Signin form. But when I add jQuery Validation Plugin it starts to jump. So the problem is: 1. I type Login (correct) 2. Than I click Password to type it, but Password's form is jumping down.</p>
  
  <pre><code>jQuery.validator.addMethod("lettersonly", function (value, element) {
      return this.optional(element) || /^[a-z0-9_-]+$/i.test(value);
  }, "Please use only a-z0-9_-");
  $('#form-signin').validate({
      rules: {
          login: {
              minlength: 3,
              maxlength: 15,
              required: true,
              lettersonly: true
          },
          password: {
              minlength: 3,
              maxlength: 15,
              required: true,
              lettersonly: true
          },
      },
      highlight: function (element) {
          $(element).closest('.control-group').addClass('has-error');
      },
      success: function (element) {
          element.closest('.control-group').removeClass('has-error');
      }
  });
  </code></pre>
  
  <h2><strong><a href="http://jsfiddle.net/4pmUW/" rel="nofollow">jsFiddle here</a></strong></h2>