unload-with-beacon.html (389B)
1 <!DOCTYPE html> 2 <script> 3 // When told, register an unload handler that will trigger a beacon to the 4 // URL given by the sender of the message. 5 window.addEventListener('message', e => { 6 var url = e.data; 7 window.addEventListener('unload', () => { 8 navigator.sendBeacon(url, 'blah'); 9 }); 10 window.parent.postMessage('navigate-away', '*'); 11 }); 12 </script>