| <!DOCTYPE HTML> | |
| <meta charset=utf-8> | |
| <meta name="viewport" content="width=device-width"> | |
| <title>Long Task Frame</title> | |
| <body> | |
| <h1>Long Task plus PostMessage</h1> | |
| <script> | |
| const begin = window.performance.now(); | |
| while (window.performance.now() < begin + 51); | |
| window.opener.postMessage('Finished.', '*'); | |
| </script> | |
| </body> |