Question on : PhP Form and a Standed Form

Question on : PhP Form and a Standed Form

My Form which has Enter name and address ect is a PHP Vaildated form, And is on the same page as the datepicker with its own Validation. The Php form comes first then the datepicker comes last.
I couldnt get both to work together on the same page, the php work's and vaildates the name & email address ect, but skipped the vaildated for the picker..is this because it goes off to the server and come's back after the checks. Or can you not have a Php Vaildation and Standed form vaildation running on the same page, OFF one Submit button.
 
The datepicker & vaildation work on there own page. But not together.
 
Thanks andy