| <!DOCTYPE html> |
| <html> |
| <body> |
| <h1>random</h1> |
| <script src="./random-cached.cgi"></script> |
| <script> |
| const lastRandomNumberKey = "lastRandomNumber"; |
| |
| window.addEventListener("message", e => { |
| if (e.data != "START") { |
| window.opener.postMessage("FAIL: unknown; " + e.data, location.origin); |
| } else { |
| // window.top.randomNumber should be set by random-cached.cgi. |
| if (window.top === undefined || window.top.randomNumber === undefined) { |
| window.opener.postMessage("FAIL: randomNumber isn't defined", |
| location.origin); |
| return; |
| } |
| |
| // If location.reload() is already triggered, lastRandomNumberKey should be |
| // stored in the sessionStorage. Otherwise, this is the first load. |
| const lastRandomNumberString = sessionStorage.getItem(lastRandomNumberKey); |
| if (lastRandomNumberString !== null) { |
| // sessionStorage returns DOMString and need to be converted to Number. |
| const lastRandomNumber = Number(lastRandomNumberString); |
| |
| // Because the random-cached.cgi is a sub-resource, and set HTTP headers |
| // to allow caching, location.reload() should follow the cache-protocol to |
| // reuse the cached resource. That is to say the randomNumber should not |
| // be changed on the reload. |
| window.opener.postMessage(lastRandomNumber == top.randomNumber |
| ? "PASS" |
| : "FAIL: randomNumber was changed", |
| location.origin); |
| } else { |
| // Store the first randomNumber to the sessionStorage, and call reload(). |
| // This window will send "READY" again, then receive "START". |
| sessionStorage.setItem(lastRandomNumberKey, top.randomNumber); |
| location.reload(); |
| } |
| } |
| }, false); |
| |
| // Send "READY" message first so that parent window can ensure to send messages. |
| window.opener.postMessage("READY", location.origin); |
| </script> |
| </body> |
| </html> |
