title_body: Can a PDF run scripts or code? Can a PDF run JavaScript?
  
  If yes what are the limitations of running scripts in a PDF when compared to a browser?
  
  Can it do network requests using JS?
  
  Can it run other types of scripts?
  
  Is JavaScript used to submit embedded forms?
upvoted_answer: Yes, it can JavaScript or what they call as Acrobat Javascript , but not all the PDF viewer can are designed to follow the Adobe Javascript API. There are few limitations defined in the API, it can make Ajax network calls but no it cannot run any other then the JavaScript  as of now.
  
  But you can disable it by 
  
  
  Select Edit>Preferences. 
  Select the JavaScript Category. 
  Uncheck the Enable Acrobat JavaScript' option.