pageVisibilityTracking.js

(function pageVisibility(){  
  
  function initializeTracking(){
    //...
  }

  function handleVisibilityChange(event){
    if(document.hidden){
      return;
    }
    event.target.removeEventListener(event.type, handleVisibilityChange);
    initializeTracking();    
  }

  function initWhenVisible(){ 
    if (typeof document.addEventListener === "undefined" || typeof document.hidden === "undefined") {
      ga('send', 'event', 'browser support features', 'visibility', 'unable to handle visibility API');
      initializeTracking();    
    } else {
      document.addEventListener(visibilityChange, handleVisibilityChange, false);
    }
  };

  var hidden, visibilityChange; 

  if (typeof document.hidden !== "undefined") { // Opera 12.10 and Firefox 18 and later support 
    hidden = "hidden";
    visibilityChange = "visibilitychange";
  } else if (typeof document.msHidden !== "undefined") {
    hidden = "msHidden";
    visibilityChange = "msvisibilitychange";
  } else if (typeof document.webkitHidden !== "undefined") {
    hidden = "webkitHidden";
    visibilityChange = "webkitvisibilitychange";
  }

  if(document.hidden){
    initWhenVisible();
  } else {
    initializeTracking();
  }
})();