如何使用JSON和JavaScript为webapp创建本地数据库

var request = indexedDB.open('myDatabase', 1);

request.onupgradeneeded = function(event) {
  var db = event.target.result;
  var objectStore = db.createObjectStore('myObjectStore', { keyPath: 'id' });
};

request.onsuccess = function(event) {
  var db = event.target.result;
  var transaction = db.transaction(['myObjectStore'], 'readwrite');
  var objectStore = transaction.objectStore('myObjectStore');
  
  var data = { id: 1, name: 'John Doe', age: 30 };
  var addRequest = objectStore.add(data);
  
  addRequest.onsuccess = function(event) {
    console.log('Data added successfully');
  };
};

request.onsuccess = function(event) {
  var db = event.target.result;
  var transaction = db.transaction(['myObjectStore'], 'readonly');
  var objectStore = transaction.objectStore('myObjectStore');
  
  var getRequest = objectStore.get(1);
  
  getRequest.onsuccess = function(event) {
    var data = event.target.result;
    console.log(data);
  };
};

request.onsuccess = function(event) {
  var db = event.target.result;
  var transaction = db.transaction(['myObjectStore'], 'readwrite');
  var objectStore = transaction.objectStore('myObjectStore');
  
  var updateRequest = objectStore.put({ id: 1, name: 'Jane Smith', age: 35 });
  
  updateRequest.onsuccess = function(event) {
    console.log('Data updated successfully');
  };
};

request.onsuccess = function(event) {
  var db = event.target.result;
  var transaction = db.transaction(['myObjectStore'], 'readwrite');
  var objectStore = transaction.objectStore('myObjectStore');
  
  var deleteRequest = objectStore.delete(1);
  
  deleteRequest.onsuccess = function(event) {
    console.log('Data deleted successfully');
  };
};