I've found a solution.In the "initialization" event script write this:this.mandatory = 'error'this.mandatoryMessage = 'Please sign the document';

I make an PDF form that contain text fields, signature field and submit button. Some text fields on form are required field. User can't send form by email until requred fields are empty. I want to do that user can't send form by email until signature fields is is empty. Is it possible?I guess there ...