How to send analytics

Use the page event :

visibilitychange

function checkVisibilityControl() { if (typeof document.hidden !== "undefined") { return { hidden: "hidden", visibilityChange: "visibilitychange", }// Opera 12.10 and Firefox 18 and later support } if (typeof document.msHidden !== "undefined") { return { hidden: "msHidden", visibilityChange: "msvisibilitychange" } } if (typeof document.webkitHidden !== "undefined") { return { hidden: "webkitHidden", visibilityChange: "webkitvisibilitychange" } } return { hidden: '', visibilityChange: 'pagehide' } }

in order to send the event use the navigator.sendBeacon (doesn't allows for getting errors), or use the fetch api, which allows for dealing with errors and use the parameter 'keepalive' : true, this is to avoid the request to be interrupted in case browser close.