Executes a callback when an element's visibility changes
Example: https://iprodev.github.io/jquery.visibilityState/
// Using plugin mode$("#tester").visibilityState(function(isVisible){if(isVisible){// do something here when element visibled.}else{// do something here when element hidden.}});// Using event mode$("#tester").on('visible',function(){// do something here when element visibled.});$("#tester").on('hidden',function(){// do something here when element hidden.});