How to make a button hide?

[Lilit]

Hello. In my project I have two buttons, which you click to go to the previous or to the next page. Everything works fine, but I also want Previous button to hide when there is no previous page, and the same with Next button. Can’t figure out what should I do in Actions editor to achieve this?

[Michael]

You need to use condition:

document.currentPageNumber > 0

document.currentPageNumber < document.countPages - 1

or

function() {
   if (document.currentPageNumber < document.countPages - 1 )
      return true
   else 
      return false
}