我正在尝试为 Firefox OS 创建一个应用程序，它基本上需要使用 IndexedDB 存储一些数据。
当用户单击提交按钮时调用 store() 函数，这会导致创建用户提交表单的名称和描述变量。
但是，我不断收到一个参考错误，说我的 db 对象未定义。任何想法为什么会发生这种情况？
这是我当前的代码：-
function store () {
// create the transaction with 1st parameter is the list of stores and the second specifies
// a flag for the readwrite option
var transaction = db.transaction([ 'Apps' ], 'readwrite');
//Create the Object to be saved i.e. our App details
var value = {};
value.name = name;
value.desc = description;
// add the details to the store
var store = transaction.objectStore('Apps');
var request = store.add(value);
request.onsuccess = function (e) {
alert("Your App data has been saved");
};
request.onerror = function (e) {
alert("Error in saving the App data. Reason : " + e.value);
}
}
$(document).ready(function(){
// variable which will hold the database connection
var db;
if (window.indexedDB) {
console.log("IndexedDB is supported");
}
else {
alert("Indexed DB is not supported!");
}
// open the database
// 1st parameter : Database name. We are using the name 'Appsdb'
// 2nd parameter is the version of the database.
var request = indexedDB.open('Appsdb', 1);
request.onsuccess = function (e) {
// e.target.result has the connection to the database
db = e.target.result;
console.log(db);
console.log("DB Opened!");
}
request.onerror = function (e) {
console.log(e);
};
// this will fire when the version of the database changes
// We can only create Object stores in a versionchange transaction.
request.onupgradeneeded = function (e) {
// e.target.result holds the connection to database
db = e.target.result;
if (db.objectStoreNames.contains("Apps")) {
db.deleteObjectStore("Apps");
}
// create a store named 'Apps'
// 1st parameter is the store name
// 2nd parameter is the key field that we can specify here. Here we have opted for autoIncrement but it could be your
// own provided value also.
var objectStore = db.createObjectStore('Apps', { keyPath: 'id', autoIncrement: true });
console.log("Object Store has been created");
};
});