malsup/form — pull request #264 by zealotous (2012-12-26 09:41:53+00:00)
Title: fix error - Uncaught TypeError

Fixes error in jquery.form.js, which cause type error
when form has inputs with 'undefined' values.
As $('').attr('value', undefined) === $('').attr('value')
the return of this construction is not jQuery collection
but actual value, and thus doesn't have appendTo member-method.