Help create script in print button

Hi, please help me.

i create a button and input under script, it's run when click button:

var pp = this.getPrintParams();

pp.firstPage = this.pageNum;

pp.lastPage = pp.firstPage;

pp.interactive = pp.constants.interactionLevel.full;

this.print(pp);

When i create sercurity for that file and dissable default print then it not working.

How to validate form before print document?