IndexedDB All In One

https://developer.mozilla.org/en-US/docs/Web/API/IndexedDB_API

https://developer.mozilla.org/zh-CN/docs/Web/API/IDBObjectStore

Indexed Database API 2.0

W3C Recommendation, 30 January 2018

https://www.w3.org/TR/IndexedDB/

blogs

https://javascript.ruanyifeng.com/bom/indexeddb.html#indexeddb-对象

open / create



let log = console.log;

const openRequest = window.indexedDB.open("idb", 1);

let db;

openRequest.onupgradeneeded = function (e) {

    log("DB Upgrading...", e);

    // db = e.target.result;

}

openRequest.onsuccess = function (e) {

    log("Open DB Success!", e);

    db = openRequest.result;

    log(`DB =`, db);

};

openRequest.onerror = function (e) {

    log("Open DB Error", e);

};

delete DB



let log = console.log;

const DBDeleteRequest = window.indexedDB.deleteDatabase("idb");

DBDeleteRequest.onerror = function (e) {

    log("Delete DB Error", e);

};

DBDeleteRequest.onsuccess = function (e) {

    log("Delete DB Success", e);

};

IDBObjectStore 对象

https://wangdoc.com/javascript/bom/indexeddb.html#idbobjectstore-对象



// DBOpenRequest.

// IDBDatabase

// IDBTransaction

// IDBObjectStore

// DBRequest.

let IDBTransaction = db.transaction(['test'], 'readonly');

let  IDBObjectStore = IDBTransaction.objectStore('test');

objectStore.add(value, key)

objectStore.put(item, key)

objectStore.clear()

objectStore.delete(Key)

IDBObjectStore.count(key)

objectStore.getKey(key)

objectStore.get(key)

// 获取所有记录

objectStore.getAll()

// 获取所有符合指定主键或 IDBKeyRange 的记录

objectStore.getAll(query)

// 指定获取记录的数量

objectStore.getAll(query, count)

// 获取所有记录的主键

objectStore.getAllKeys()

// 获取所有符合条件的主键

objectStore.getAllKeys(query)

// 指定获取主键的数量

objectStore.getAllKeys(query, count)

objectStore.index(name)

objectStore.createIndex(indexName, keyPath, objectParameters)

objectStore.deleteIndex(indexName)

IDBObjectStore.openCursor()

IDBObjectStore.openKeyCursor()

/*

IDBObjectStore.indexNames：返回一个类似数组的对象（DOMStringList），包含了当前对象仓库的所有索引。

IDBObjectStore.keyPath：返回当前对象仓库的主键。

IDBObjectStore.name：返回当前对象仓库的名称。

IDBObjectStore.transaction：返回当前对象仓库所属的事务对象。

IDBObjectStore.autoIncrement：布尔值，表示主键是否会自动递增。

*/



let t = db.transaction(['test'], 'readonly');

let store = t.objectStore('test');

let cursor = store.openCursor();

cursor.onsuccess = function (event) {

  let res = event.target.result;

  if (res) {

    console.log('Key', res.key);

    console.dir('Data', res.value);

    res.continue();

  }

}

Web Workers

https://developer.mozilla.org/zh-CN/docs/Web/API/Web_Workers_API

https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Functions_and_classes_available_to_workers

demo



"use strict";

/**

 *

 * @author xgqfrms

 * @license MIT

 * @copyright xgqfrms

 *

 * @description IndexedDB

 * @augments

 * @example

 * @link

 *

 */

// const IndexedDB = (datas = [], debug = false) => {

//     let result = ``;

//     // do something...

//     return result;

// };

// export default IndexedDB;

// export {

//     IndexedDB,

// };

let log = console.log;

// 主线程

const url = `https://cdn.xgqfrms.xyz/json/xgqfrms.json`;

const css = `

    color: #f0f;

    font-size: 23px;

`;

let worker = new Worker("./idb-worker.js");

// 发送数据

worker.postMessage(url);

// 接收数据

worker.onmessage = function(e) {

    log(`\n%c worker 线程 e = `, css, e);

    let json = e.data || {};

    log(`%c worker 线程 data = `, css, JSON.stringify(json, null, 4));

}

setTimeout(() => {

    // 完成任务后, 关掉 Worker

    worker.terminate();

}, 1000 * 100);



"use strict";

/**

 *

 * @author xgqfrms

 * @license MIT

 * @copyright xgqfrms

 *

 * @description IndexedDBWorker

 * @augments

 * @example

 * @link

 *

 */

let log = console.log;

log(`hello world!`);

// worker 线程

const css = `

    color: #0ff;

    font-size: 23px;

`;

const css_fd = `

    color: #0f0;

    font-size: 23px;

`;

// callback function

onmessage = function (e){

    console.log(`\n%c 主线程 e = `, css, e);

    // evt.data 接收数据

    let url = e.data;

    // fetch data

    const datas = [];

    // decodeURI()

    console.log(`%c 主线程 url = `, css, `"${url}"`);

    fetch(url)

    .then(res => res.json())

    .then(

        (json) => {

            // console.log(`fetched json = \n`, JSON.stringify(json, null, 4));

            let userInfos = json.user;

            console.log(`%c userInfos = `, css_fd, JSON.stringify(userInfos, null, 4));

            datas.push(userInfos);

            postMessage(userInfos);

            // 发送数据

        }

    )

    .catch(err => log(`fetch error = \n`, err));

}

// const IndexedDBWorker = (datas = [], debug = false) => {

//     let result = ``;

//     // do something...

//     return result;

// };

// export default IndexedDBWorker;

// export {

//     IndexedDBWorker,

// };

self & this



"use strict";

/**

 *

 * @author xgqfrms

 * @license MIT

 * @copyright xgqfrms

 *

 * @description IndexedDBWorker

 * @augments

 * @example

 * @link

 *

 */

let log = console.log;

// worker 线程

const css = `

    color: #0ff;

    font-size: 23px;

`;

const css_fd = `

    color: #0f0;

    font-size: 23px;

`;

// self 代表子线程自身，即子线程的全局对象

log(`worker self =`, self);

// DedicatedWorkerGlobalScope

let name = self.name;

log(`worker name =`, name);

// BAD

// self.addEventListener(`meassge`, function (e) {

//     log(`self.addEventListener("meassge", function (e) {});`);

//     log(`\n%c 主线程 e = `, css, e);

//     // evt.data 接收数据

//     let url = e.data;

//     log(`%c 主线程 url = `, css, `"${url}"`);

// });

// BAD

// self.addEventListener(`meassge`, (e) => {

//     log(`self.addEventListener("meassge", (e) => {});`);

//     log(`\n%c 主线程 e = `, css, e);

//     // evt.data 接收数据

//     let url = e.data;

//     log(`%c 主线程 url = `, css, `"${url}"`);

// });

// 写法一 OK

// this.addEventListener("message", function (e) {

//     log(`this.addEventListener("message", function (e) {});`);

//     log(`\n%c 主线程 e = `, css, e);

//     // evt.data 接收数据

//     let url = e.data;

//     log(`%c 主线程 url = `, css, `"${url}"`);

// }, false);

// 写法二 OK

// addEventListener("message", function (e) {

//     log(`addEventListener("message", function (e) {});`);

//     log(`\n%c 主线程 e = `, css, e);

//     // evt.data 接收数据

//     let url = e.data;

//     log(`%c 主线程 url = `, css, `"${url}"`);

// }, false);

// OK

self.onmessage = function (e){

    log(`self.onmessage = function (e) {});`);

    log(`\n%c 主线程 e = `, css, e);

    // evt.data 接收数据

    let url = e.data;

    log(`%c 主线程 url = `, css, `"${url}"`);

};

// OK

// onmessage = function (e){

//     log(`onmessage = function (e) {});`);

//     log(`\n%c 主线程 e = `, css, e);

//     // evt.data 接收数据

//     let url = e.data;

//     log(`%c 主线程 url = `, css, `"${url}"`);

// };

// Worker 线程

// self.close();

// callback function

// onmessage = function (e){

//     console.log(`\n%c 主线程 e = `, css, e);

//     // evt.data 接收数据

//     let url = e.data;

//     // fetch data

//     const datas = [];

//     // decodeURI()

//     console.log(`%c 主线程 url = `, css, `"${url}"`);

//     fetch(url)

//     .then(res => res.json())

//     .then(

//         (json) => {

//             // console.log(`fetched json = \n`, JSON.stringify(json, null, 4));

//             let userInfos = json.user;

//             console.log(`%c userInfos = `, css_fd, JSON.stringify(userInfos, null, 4));

//             datas.push(userInfos);

//             postMessage(userInfos);

//             // 发送数据

//         }

//     )

//     .catch(err => log(`fetch error = \n`, err));

// };

// onmessage = (e) => {

//     let log = console.log;

//     log(`e =`, e);

//     // // TODO ??? WebSockets header & token

//     const url = `ws://10.1.64.142:8080/chat/?token=00`;

//     // const url = `ws://10.1.64.142:8080/chat/?token=03977977-6ac7-4336-b799-90358d351b5c`;

//     let ws = new WebSocket(url);

//     ws.onopen = function(e) {

//         log(`已经建立连接 open`, ws.readyState);

//         log(`e = `, e);

//         subscribe();

//     };

//     ws.onerror = function(e) {

//         log(`连接异常 error`, ws.readyState);

//         log(`e = `, e);

//     };

//     ws.onmessage = function(res) {

//         log(`A 收到消息 message`, ws.readyState);

//         let data = res.data;

//         let origin = res.origin;

//         // log(`res & e = `, res);

//         data = JSON.parse(data);

//         // log(`typeof(data) = `, typeof(data));

//         log(`res.data = `, JSON.stringify(data, null, 4));

//         log(`res.origin = `, origin);

//         // postMessage(data);

//     };

//     ws.onclose = function(e) {

//         log(`已经关闭连接 close`, ws.readyState);

//         log(`e = `, e);

//     };

//     const subscribe = () => {

//         let msg = {

//             Action: "4",

//             SendUserID: "6845488",

//             ReciveUserID: "6845422",

//             SerialNumber: "消息序列",

//             LastReciveMsgId: null,

//             LastReciveMsgIds: [{

//                 K: "6845422",

//                 V: null,

//             }],// 最后一条消息

//             AllUser: true, // 所有用户, boolean

//         };

//         log(`A 订阅所有用户消息`);

//         let str_msg = JSON.stringify(msg);

//         ws.send(str_msg);

//     };

//     let flag = setInterval(() => {

//         let uid = new Date().getTime();

//         // let msg = {

//         //     Action: "1",

//         //     SendUserID: "6845488",

//         //     ReciveUserID: "6845422",

//         //     SerialNumber: "消息序列",

//         //     Info: "消息内容 A",

//         //     MsgID: uid,

//         //     MsgType: "1", // 消息类型（1-文本、2-图片、3-表情、4-视频、5-音频）

//         // };

//         let msg = {

//             Action: "1",

//             SendUserID: "6845488",

//             ReciveUserID: "6845422",

//             SerialNumber: `A 消息序列 ${uid}`,

//             Info: "消息内容 A",

//             MsgID: uid,

//             MsgType: 1,

//         };

//         log(`A 发送消息:`, JSON.stringify(msg, null, 4));

//         let str_msg = JSON.stringify(msg);

//         ws.send(str_msg);

//         postMessage(msg);

//     }, 3000);

//     setTimeout(() => {

//         clearInterval(flag);

//     }, 60 * 1000);

// };

// const IndexedDBWorker = (datas = [], debug = false) => {

//     let result = ``;

//     // do something...

//     return result;

// };

// export default IndexedDBWorker;

// export {

//     IndexedDBWorker,

// };

bug

Failed to execute 'importScripts' on 'WorkerGlobalScope':



"use strict";

/**

 *

 * @author xgqfrms

 * @license MIT

 * @copyright xgqfrms

 *

 * @description IndexedDBWorker

 * @augments

 * @example

 * @link

 *

 */

let log = console.log;

// worker 线程

let name = self.name;

log(`worker name =`, name);

// importScripts("./set-red-point.js");

// self.importScripts("./set-red-point.js");

// self.importScripts("set-red-point.js");

onmessage = (e) => {

    let log = console.log;

    const css = `

        color: #0ff;

        font-size: 23px;

    `;

    const css_fd = `

        color: #0f0;

        font-size: 23px;

    `;

    console.log(`\n%c 主线程 e = `, css, e);

    let URI = e.data;

    // fetch data

    const datas = [];

    // decodeURI()

    // console.log(`%c 主线程 url = `, css, `"${URI}"`);

    log(`e =`, e);

    // TODO ??? WebSockets header & token

    // const url = `${URI}/?token=00`;

    const url = `ws://10.1.64.142:8080/chat/?token=00`;

    console.log(`ws url = `, url);

    // const url = `ws://10.1.64.142:8080/chat/?token=03977977-6ac7-4336-b799-90358d351b5c`;

    let ws = new WebSocket(url);

    // window.WS = ws;

    // window.ws = ws;

    // let ws = window.WS;

    // let ws = Vue.prototype.$WS;

    // log(`WS =`, window.WS);

    ws.onopen = function(e) {

        log(`已经建立连接 open`, ws.readyState);

        log(`e = `, e);

        fetchList();

        IndexDBDemo();

        // subscribe();

        // autoSendText();

    };

    ws.onerror = function(e) {

        log(`onerror ws.readyState`, ws.readyState);

        log(`连接异常 error`, ws.readyState);

        log(`e = `, e);

    };

    ws.onmessage = function(res) {

        log(`onmessage ws.readyState`, ws.readyState);

        log(`A 收到消息 message`);

        let data = res.data;

        let origin = res.origin;

        // log(`res & e = `, res);

        data = JSON.parse(data);

        // log(`typeof(data) = `, typeof(data));

        log(`res.data = `, JSON.stringify(data, null, 4));

        log(`res.origin = `, origin);

        // postMessage(data);

    };

    ws.onclose = function(e) {

        log(`onclose ws.readyState`, ws.readyState);

        log(`已经关闭连接 close`, ws.readyState);

        log(`e = `, e);

    };

    const fetchList = () => {

        let msg = {

            Action: "12",

        };

        log(`A 消息列表1`);

        let str_msg = JSON.stringify(msg);

        log(`A 消息列表`, str_msg);

        ws.send(str_msg);

    };

    const subscribe = () => {

        let msg = {

            Action: "4",

            SendUserID: "6845488",

            ReciveUserID: "6845422",

            SerialNumber: "消息序列",

            LastReciveMsgId: null,

            LastReciveMsgIds: [{

                K: "6845422",

                V: null,

            }],// 最后一条消息

            AllUser: true, // 所有用户, boolean

        };

        log(`A 订阅所有用户消息`);

        let str_msg = JSON.stringify(msg);

        ws.send(str_msg);

    };

    const autoSendText = () => {

        let flag = setInterval(() => {

            let uid = new Date().getTime();

            // let msg = {

            //     Action: "1",

            //     SendUserID: "6845488",

            //     ReciveUserID: "6845422",

            //     SerialNumber: "消息序列",

            //     Info: "消息内容 A",

            //     MsgID: uid,

            //     MsgType: "1", // 消息类型（1-文本、2-图片、3-表情、4-视频、5-音频）

            // };

            let msg = {

                Action: "1",

                SendUserID: "6845488",

                ReciveUserID: "6845422",

                SerialNumber: `A 消息序列 ${uid}`,

                Info: "消息内容 A",

                MsgID: uid,

                MsgType: 1,

            };

            log(`A 发送消息:`, JSON.stringify(msg, null, 4));

            let str_msg = JSON.stringify(msg);

            ws.send(str_msg);

            postMessage(msg);

        }, 3000);

        setTimeout(() => {

            clearInterval(flag);

        }, 60 * 1000);

    };

};

const IndexDBDemo = ( debug = false) => {

    log(`indexeddb created`)

    // let indexedDB = window.indexedDB;

    let dbVersion = 1;

    // step 01, open

    let idb_connect = indexedDB.open("test_db", dbVersion);

    // IDBOpenDBRequest & {onblocked: null, onupgradeneeded: null, source: null, transaction: null, readyState: "pending", …}

    // idb_connect.onsuccess = function(e) {

    //     let log = console.log;

    //     let db = idb_connect.result;

    //     setTimeout(() => {

    //         // index & looks up

    //         let tx = db.transaction("books", "readonly");

    //         let opened_store = tx.objectStore("books");

    //         let index = opened_store.index("by_title");

    //         // query

    //         let request = index.get("Bedrock Nights");

    //         request.onsuccess = function() {

    //             let matching = request.result;

    //             if (matching !== undefined) {

    //                 let {

    //                     isbn,

    //                     title,

    //                     author,

    //                 } = matching;

    //                 log(`A match was found.`, isbn, title, author);

    //             } else {

    //                 log(`No match was found.`);

    //             }

    //         };

    //     }, 3000);

    // };

    idb_connect.onsuccess = function(e) {

        let readyState = idb_connect.readyState;

        console.log("Success creating/accessing IndexedDB database", readyState);

        let idb = idb_connect.result;

        // step 02, idb

        idb.onerror = function(e) {

            let name = idb.name;

            let version = idb.version;

            let objectStoreNames = idb.objectStoreNames;

            let length = objectStoreNames.length;

            let error = idb.error;

            console.log("Error creating/accessing IndexedDB", error);

        };

        idb.onabort = function(e) {

            let name = idb.name;

            let version = idb.version;

            let objectStoreNames = idb.objectStoreNames;

            let length = objectStoreNames.length;

            console.log("onabort & IndexedDB", name, version);

        };

        idb.onversionchange = function(e) {

            let name = idb.name;

            let version = idb.version;

            let objectStoreNames = idb.objectStoreNames;

            let length = objectStoreNames.length;

            console.log("onversionchange & IndexedDB", name, version);

        };

        idb.onclose = function(e) {

            let name = idb.name;

            let version = idb.version;

            let objectStoreNames = idb.objectStoreNames;

            let length = objectStoreNames.length;

            console.log("onclose & IndexedDB", name, version);

        };

    };

    idb_connect.onerror = function(e) {

        let error = idb_connect.error;

        console.log("Error creating/accessing IndexedDB database", error);

    };

    idb_connect.onblocked = function(e) {

        let source = idb_connect.source;

        console.log("onblocked & IndexedDB database", source, transaction);

    };

    // idb_connect.onupgradeneeded = function(e) {

    //     let source = idb_connect.source;

    //     let transaction = idb_connect.transaction;

    //     console.log("onupgradeneeded & IndexedDB database", source, transaction);

    // };

    // connect upgradeneeded

    idb_connect.onupgradeneeded = function(e) {

        let {

            // name,

            // version,

            // objectStoreNames,

            // error,

            source,

            transaction,

        } = idb_connect;

        // let source = idb_connect.source;

        // let transaction = idb_connect.transaction;

        log("onupgradeneeded & IndexedDB database", source, transaction);

        // The database did not previously exist, so create object stores and indexes.

        let db = idb_connect.result;

        let store = db.createObjectStore("books", {keyPath: "isbn"});

        // create index

        let titleIndex = store.createIndex("by_title", "title", {unique: true});

        let authorIndex = store.createIndex("by_author", "author");

        // Populate with initial data.

        store.put({

            title: "Quarry Memories",

            author: "Fred",

            isbn: 123456,

        });

        store.put({

            title: "Water Buffaloes",

            author: "Fred",

            isbn: 234567,

        });

        store.put({

            title: "Bedrock Nights",

            author: "Barney",

            isbn: 345678,

        });

        setTimeout(() => {

            // transaction & update

            let tx = db.transaction("books", "readwrite");

            let opened_store = tx.objectStore("books");

            opened_store.put({

                title: "Quarry Memories",

                author: "Fred",

                isbn: 123456,

            });

            opened_store.put({

                title: "Water Buffaloes",

                author: "Fred",

                isbn: 234567,

            });

            opened_store.put({

                title: "Bedrock Nights",

                author: "Barney",

                isbn: 345678,

            });

            tx.oncomplete = function() {

                log(`All requests have succeeded and the transaction has committed.`);

            };

        }, 3000);

        setTimeout(() => {

            // index & looks up

            let tx = db.transaction("books", "readonly");

            let opened_store = tx.objectStore("books");

            let index = opened_store.index("by_title");

            // query

            let request = index.get("Bedrock Nights");

            request.onsuccess = function() {

                let matching = request.result;

                if (matching !== undefined) {

                    let {

                        isbn,

                        title,

                        author,

                    } = matching;

                    log(`A match was found.`, isbn, title, author);

                } else {

                    log(`No match was found.`);

                }

            };

        }, 3000);

    };

    return idb_connect;

};

// importScripts("./set-red-point.js");

// self.importScripts("./set-red-point.js");

// Worker 线程

// setTimeout(() => {

//     log(`\n%c 关掉 worker 线程`, css);

//     // 完成任务后, 关掉 Worker

//     // worker.terminate();

//     self.close();

// }, 1000 * 10);

// const IndexedDBWorker = (datas = [], debug = false) => {

//     let result = ``;

//     // do something...

//     return result;

// };

// export default IndexedDBWorker;

// export {

//     IndexedDBWorker,

// };

refs

xgqfrms 2012-2020

www.cnblogs.com 发布文章使用：只允许注册用户才可以访问！

IndexedDB All In One的更多相关文章

IndexedDB（本地存储）
var students = [{ id: 1001, name: "Byron", age: 24 }, { id: 1002, name: "Frank", ...
HTML5存储之 indexedDB
IndexeDB是HTML5 重要的一部分,它是一种轻量级的NOSQL数据库.对创建具有丰富本地存储数据的数据密集型的离线HTML5 Web 应用程序很有用. IndexedDB是为了能够在客户端存储 ...
Notes:indexedDB使用
indexedDB是浏览器端保存结构化数据的一种数据库,类似于mysql,oracle等数据库,但indexedDB使用对象存储数据,而不是用表. indexedDB是全局的宿主对象,使用window ...
HTML5本地存储——IndexedDB（一：基本使用）
在HTML5本地存储——Web SQL Database提到过Web SQL Database实际上已经被废弃,而HTML5的支持的本地存储实际上变成了 Web Storage(Local Stora ...
IndexedDB参考资料网址
IndexedDB:浏览器里内置的数据库, Web骇客 http://www.webhek.com/indexeddb/ 前端的数据库:IndexedDB入门(很全面) http://web.jobb ...
HTML5本地存储——IndexedDB（二：索引）
在HTML5本地存储——IndexedDB(一:基本使用)中介绍了关于IndexedDB的基本使用方法,很不过瘾,这篇我们来看看indexedDB的杀器——索引. 熟悉数据库的同学都知道索引的一个好处 ...
js IndexedDB：浏览器端数据库的demo实例
IndexedDB具有以下特点. (1)键值对储存. IndexedDB内部采用对象仓库(object store)存放数据.所有类型的数据都可以直接存入,包括JavaScript对象.在对象仓库中, ...
Web数据持久化存储IndexedDB（不常用）
IndexedDB是在浏览器中保存结构化数据的一种数据库,为了替换WebSQL(标准已废弃,但被广泛支持)而出现.IndexedDB使用NoSQL的形式来操作数据库,保存和读取是JavaScript对 ...
[转]使用 HTML5 IndexedDB API
本地数据持久性提高了 Web 应用程序可访问性和移动应用程序响应能力索引数据库 (IndexedDB) API(作为 HTML5 的一部分)对创建具有丰富本地存储数据的数据密集型的离线 HTML5 ...
HTML5 indexedDB数据库的入门学习（二）
上一篇关于indexedDB的学习笔记主要写了indexedDB数据库的基本操作—增删改查:但是为什么我们要用indexedDB呢?为什么indexedDB受到了开发者们的青睐呢?最主要的就是inde ...

随机推荐

http2 http1 对比
RFC 7540 - Hypertext Transfer Protocol Version 2 (HTTP/2) https://tools.ietf.org/html/rfc7540#page-4 ...
TypeScript基本类型
类型注解作用:相当于强类型语言中的类型声明语法:(变量/函数):type 数据类型新建src/datatype.ts,里面定义各种类型的数据原始类型: let bool: boolean = ...
JAD 反编译
自动拆装箱对于基本类型和包装类型之间的转换,通过xxxValue()和valueOf()两个方法完成自动拆装箱,使用jad进行反编译可以看到该过程: public class Demo { publ ...
通过动态构建Expression Select表达式并创建动态类型来控制Property可见性
通过动态构建Expression Select表达式并创建动态类型来控制Property可见性项目中经常遇到的一个场景,根据当前登录用户权限,仅返回权限内可见的内容.参考了很多开源框架,更多的是在V ...
一：优化Docker中的Spring Boot应用：单层镜像方法
优化Docker中的Spring Boot应用:单层镜像方法 1.Docker关键概念 2.镜像层内容很重要 3.镜像层影响部署 4.Docker中的Spring Boot应用 5.单层方法 5.1 ...
python----类，面向对象（封装、继承、多态）（属性，方法）
什么是对象? 对象是内存中专门用来存储数据的一块区域对象中可以存放各种数据(数字.代码等) 对象由三部分组成(1,对象标识(id)2,对象类型(type)3,对象的值(value)) 面向对象编程是 ...
JavaWeb-tomcat安装（Unsupported major.minor version 51.0/startup.bat闪退）
JavaWeb-tomcat安装(Unsupported major.minor version 51.0) 一启动startup.bat 出错i 今天安装tomcat出错,折腾了一下午,收获了许多 ...
redis分布式锁的这些坑，我怀疑你是假的开发
摘要:用锁遇到过哪些问题? 一.白话分布式什么是分布式,用最简单的话来说,就是为了较低单个服务器的压力,将功能分布在不同的机器上面:就比如: 本来一个程序员可以完成一个项目:需求->设计-&g ...
力扣643.子数组最大平均数I-C语言实现
题目给定 n 个整数,找出平均数最大且长度为 k 的连续子数组,并输出该最大平均数. 示例: 输入:[1,12,-5,-6,50,3], k = 4 输出:12.75 解释:最大平均数 (12-5- ...
初窥 Python 的 import 机制
本文适合有 Python 基础的小伙伴进阶学习作者:pwwang 一.前言本文基于开源项目: https://github.com/pwwang/python-import-system 补充扩展 ...

IndexedDB All In One

IndexedDB All In One

Indexed Database API 2.0

open / create

delete DB

IDBObjectStore 对象

Web Workers

self & this

bug

refs

xgqfrms 2012-2020

www.cnblogs.com 发布文章使用：只允许注册用户才可以访问！

IndexedDB All In One的更多相关文章

随机推荐

热门专题

IndexedDB All In One

IndexedDB All In One

Indexed Database API 2.0

open / create

delete DB

IDBObjectStore 对象

Web Workers

self & this

bug

refs

xgqfrms 2012-2020 www.cnblogs.com 发布文章使用：只允许注册用户才可以访问！

IndexedDB All In One的更多相关文章

随机推荐

热门专题

xgqfrms 2012-2020

www.cnblogs.com 发布文章使用：只允许注册用户才可以访问！