| <!doctype html> |
| <meta charset="utf-8"> |
| <script> |
| const dbName = "users"; |
| |
| // Create the database at v1 and detect success via `onsuccess`. |
| function createDatabase() { |
| return new Promise((resolve, reject) => { |
| var dbRequest = window.indexedDB.open(dbName, 1); |
| dbRequest.onblocked = () => reject(); |
| dbRequest.onerror = () => reject(); |
| dbRequest.onsuccess = (e) => { |
| e.target.result.close(); |
| resolve(); |
| } |
| }); |
| } |
| |
| // Open the database at v2 and detect existance via `onupgradeneeded`. |
| function doesDatabaseExist() { |
| let didExist = false; |
| return new Promise((resolve, reject) => { |
| var dbRequest = window.indexedDB.open(dbName, 2); |
| dbRequest.onblocked = () => reject(); |
| dbRequest.onerror = () => reject(); |
| dbRequest.onsuccess = (e) => { |
| e.target.result.close(); |
| deleteDatabase().then(() => resolve(didExist)); |
| }; |
| dbRequest.onupgradeneeded = (e) => { |
| didExist = e.oldVersion != 0; |
| }; |
| }); |
| } |
| |
| // Delete the database and detect success via `onsuccess`. |
| function deleteDatabase() { |
| return new Promise((resolve, reject) => { |
| var dbRequest = window.indexedDB.deleteDatabase(dbName); |
| dbRequest.onblocked = () => reject(); |
| dbRequest.onerror = () => reject(); |
| dbRequest.onsuccess = () => resolve(); |
| }); |
| } |
| |
| window.addEventListener("load", () => { |
| if (!parent.opener) { |
| // Step 2 |
| createDatabase().then(() => { |
| parent.postMessage( |
| {message: "same-site iframe loaded"}, |
| parent.origin, |
| ); |
| }); |
| } else { |
| // Step 4 |
| doesDatabaseExist().then((result) => { |
| parent.opener.postMessage( |
| { |
| message: "cross-site iframe loaded", |
| doesDatabaseExist: result, |
| }, |
| parent.opener.origin, |
| ); |
| }); |
| } |
| }); |
| |
| // Step 6 |
| window.addEventListener("message", (e) => { |
| if (e.data.message == "delete database") { |
| deleteDatabase().then(() => { |
| e.source.postMessage( |
| {message: "database deleted"}, |
| e.source.origin, |
| ); |
| }); |
| } |
| }); |
| </script> |
