HTML5 Web Storage

简介

 

HTML5 web storage, better than cookies.

• more secure and faster
• data store in name/value pairs
• the storage limit is at least 5MB

 

 

1. 发展过程：

 

 

 

2. 浏览器支持情况：

 

 

 

3. HTML5 Web Storage 提供如下两种对象：

 

• window.localStorage - stores data with no expiration date  没有过期日期
• sessionStorage - stores data for one session (data is lost when the tab is closed) 

　  两者使用没有区别，下面使用中以localStorage举例

 

4. 基本使用：

 

使用前应该判断浏览器是否支持

if(typeof(Storage)!=="undefined")
  {
  // Code for localStorage/sessionStorage.
  }
else
  {
  // Sorry! No Web Storage support..
  }

使用：

localStorage.setItem("name","wish");  // store
localStorage.name="wish";
localStorage["name"]="wish";

localStorage.getItem("name");  //retrieve

localStorage.removeItem("name");  //remove

localStorage.clear();      //删除所有

localStorage.key(i);   // get key

 

 

注意： localStorage calls toString on all stored values.  所以如果是数字等类型也会转化为String

 

5.例子

 

 

 

在google resource中查看：removeItem后改记录消失

 

简单页面访问计数：

使用localStorage：

if (localStorage.visitcount)
  {
  localStorage.visitcount = Number(localStorage.visitcount) + 1; //需要转换类型
  }
else
  {
  localStorage.visitcount= 1;
  }
document.getElementById("visitTimes").innerHTML="You have visited " +
localStorage.visitcount+ " time(s).";

 

使用sessionStorage：

if (sessionStorage.visitcount)
  {
  sessionStorage.visitcount = Number(sessionStorage.visitcount) + 1; //需要转换类型
  }
else
  {
  sessionStorage.visitcount= 1;
  }
document.getElementById("visitTimes").innerHTML="You have visited " +
sessionStorage.visitcount+ " time(s).";

 

6.github上store.js

　　github地址：https://github.com/marcuswestin/store.js/

• 基于localStorage  ：store.js exposes a simple API for cross browser local storage
• 无兼容性问题：store.js uses localStorage when available, and falls back on the userData behavior in IE6 and IE7
• 存储时不会tostring： store.js uses JSON.stringify() and JSON.parse() on each call to store.set() and store.get()

　　基本使用如下：

store.set('name', 'wish')  // Store

store.get('name')   // Get 

store.remove('username')  // Remove 'name'

store.clear()  // Clear all keys

 

参考：http://www.w3schools.com/html/html5_webstorage.asp

       http://www.cnblogs.com/xiaowei0705/archive/2011/04/19/2021372.html