Remove depreated :input selector and just use attribute selectors since we are already searching within form context.

Author: javierjulio

jquery.form.js

@@ -286,7 +286,7 @@ $.fn.ajaxSubmit = function(options) {
         var useProp = !!$.fn.prop;
         var deferred = $.Deferred();
 
-        if ($(':input[name=submit],:input[id=submit]', form).length) {
+        if ($('[name=submit],[id=submit]', form).length) {
             // if there is an input with a name or id of 'submit' then we won't be
             // able to invoke the submit fn on the form (at least not x-browser)
             alert('Error: Form elements must not have name or id of "submit".');