Check Box for 2 different .pdf files

I am trying to have two different .pdf forms, and when I check a box in o开发者_StackOverflowne it will show in the other, then when all the boxes are checked it will check another box in the second .pdf.

How would I do this?

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I believe you will have to write some javascript code inside your pdf files. This will do the job for the first case, but I am not sure if Acrobat Reader will allow you to do modifications on an external file from javascript... If it does allow you, I would consider it a security hole.