Why the button submit is not executed

Why the button submit is not executed

Hello,
I use a modal window to display results of a query. However, the modal is displayed but I don't have results into this modal, because of the button submit which is not read by the program.
I have tested my code without the instruction if (isset($_POST['submit'])) ... and the result is :
all fields are displayed, like this my request has been executed but the conditions are not taken into account.
my code :
http://codeshare.io/zM6JA