簡介

Html5 web storage, better than cookIEs.

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

 

 

1. 發展過程：

 

 

 

2. 浏覽器支持情況：

 

 

 

3. Html5 Web Storage 提供如下兩種對象：

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

　  兩者使用沒有區別，下面使用中以localStorage舉例

 

4. 基本使用：

 

使用前應該判斷浏覽器是否支持

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();      //刪除所有
 localStorage.key(i);   // get key

 

注意： localStorage calls toString on all stored values.  所以如果是數字等類型也會轉化為String

5.例子

在google resource中查看：removeItem後改記錄消失

簡單頁面訪問計數：

使用localStorage：

if (localStorage.visitcount)
  {
  localStorage.visitcount = Number(localStorage.visitcount) + 1; //需要轉換類型
  }
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; //需要轉換類型
  }
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/

• 基於localStorage  ：store.JS exposes a simple API for cross browser local storage
• 無兼容性問題：store.JS uses localStorage when available, and falls back on the userData behavior in IE6 and IE7
• 存儲時不會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