Prevent changing contents of fields on a pdf form

[joken99]

Years ago I had a way to save a pdf file with information saved in the fields and the information was locked to prevent changes.  I think there was a button on the form labeled protect and it locked the form somehow.  Please let me know if anyone knows how I may have done this.  A mind is a terrible thing to waste!! 

[Thom Parker]

All fields have a readonly property. Set this to true and the user's can't edit the field. It'll need to be done with a script.

this.getField("MyField").readonly = true;

Repeat this line of code for all fields that need to be locked.  Place in a script on a button MouseUp.