fix(form): optimized disabled detection

The code to detect a field is disabled could not handle fields under fieldset[disabled]

Author: jameschenjav

src/definitions/behaviors/form.js

@@ -1128,7 +1128,7 @@ $.fn.form = function(parameters) {
                 $elGroup   = $(el).closest($group),
                 isCheckbox = ($el.filter(selector.checkbox).length > 0),
                 isRequired = $el.prop('required') || $elGroup.hasClass(className.required) || $elGroup.parent().hasClass(className.required),
-                isDisabled = $el.prop('disabled') || $elGroup.hasClass(className.disabled) || $elGroup.parent().hasClass(className.disabled),
+                isDisabled = $el.is(':disabled') || $elGroup.hasClass(className.disabled) || $elGroup.parent().hasClass(className.disabled),
                 validation = module.get.validation($el),
                 hasEmptyRule = validation
                   ? $.grep(validation.rules, function(rule) { return rule.type == "empty" }) !== 0
@@ -1207,13 +1207,7 @@ $.fn.form = function(parameters) {
               module.debug('Using field name as identifier', identifier);
               field.identifier = identifier;
             }
-            var isDisabled = true;
-            $.each($field, function(){
-                if(!$(this).prop('disabled')) {
-                  isDisabled = false;
-                  return false;
-                }
-            });
+            var isDisabled = !$field.filter(':not(:disabled)').length;
             if(isDisabled) {
               module.debug('Field is disabled. Skipping', identifier);
             }