How don't execute a file.

How don't execute a file.

Hi,
I would like to know how to  prevent the execution of the specified file when you press the cancel button.
I have a html form on jquery dialog to input user name and password. The two input text are required attribute. When I press on "access" button I run a php file and then I access to my system, when I press on "close" button I would like to close the dialog, but it appers the required message.

Demo: http://jsfiddle.net/xzwmwqsz/76/

Thanks in advance.

Tegatti