Empty field prevents user from signing

Question

Good afternoon,
How do I prevent a user from digitally signing the document if there is a blank field.
The issue I am having is that the digital signature prompt pops up. When the user signs, the document saves. After that is executed, my java code executes clearing the signature.
The thing is we have a saved document with a signature in there.
Is there any way I can have a javascipt prevent the digital signature prompt if a field is blank?

Answer 1

I think I found a solution but it is not working as I would hope. I decided to add in a text field above the signature block. See code below:
if(this.getField("PE1").value=="" || this.getField("PE2").value=="" || this.getField("PE3").value=="" || this.getField("PE4").value=="" || this.getField("PE5").value=="" || this.getField("PE6").value==""){
    this.getField("Text100").value="To digitally sign, you must input all ratings in page 2"
    this.getField("Signature37").readonly=false
    else
    this.getField("Text100").value=""
    this.getField("Signature37").readonly=true
It is not executing the read only.
How do I fix this?