localStorage變更事件當前頁響應新解


html5的localStorage相信大家都是很熟悉了,但是在chrome等支持該對象的瀏覽器中(ie10除外),如果你監聽 storage變更事件你就會發現,當數據發生變化時本頁是監聽不到storage事件變更消息的。而同域的其他打開的頁面反而監聽到了該消息。悲劇不?

以上的機制應該是無可厚非的,但是對於單頁app或者數據驅動的頁面展現來說,這是一個讓人抓狂的規事情。awen在開發中為了實現一個純數據驅動的單頁app機制。不得不面對這個問題,經過測試終於實現了本頁面locaStorage變更監聽。

基本原理如下:

1  重新生成一個對象,包裝localStorage原生方法:

var Storage = {
        setItem : function(k,v){
          localStorage.setItem(k,v);
          ......
        },
        removeItem : function(k){
          localStorage.removeItem(k);
               .......
        },
        getItem :
            ...
      }

2 在能引起storage變更時間的操作接口中,手動觸發StorageEvent事件

  比如removeItem的實現中,你就需要初始化並觸發StorageEvent事件:

var se = document.createEvent("StorageEvent");
se.initStorageEvent('storage', false, false, key, oldval, newval, url, storage);
window.dispatchEvent(se);

3 通過自封裝的Storage對象操作,並在當前頁監聽:

 

window.addEventListener("storage",function(e){
     console.log(e);
},false);

Storage.addItem('test','小朋友愛吃糖');

 

到此為止。StorageEvent的當前頁面監聽問題就解決了,爽不?

轉載:http://www.cnblogs.com/cczw/p/3196195.html

HTML5 localStorage and sessionStorage

HTML5 提供兩種web存儲方法,localStorage 與 sessionStorage


localStorage 與 sessionStorage 區別

localStorage沒有過期時間,只要不clear或remove,數據會一直保存。

sessionStorage 針對一個session進行數據存儲,生命周期與session相同,當用戶關閉瀏覽器后,數據將被刪除。


特點:

1.localStorage 默認支持的容量為一個站5M,當調用setItem超過上限時,會觸發QuotaExceededError異常。當然有些瀏覽器支持修改容量上限,但為了兼容其他瀏覽器,最好按5M的容量來使用。

2.localStorage 是以key-value形式保存數據的,key和value只能是字符串格式。因此數字1保存后,會轉換成字符串1。

3.localStorage 的寫入與讀取寫法有以下幾種:

localStorage.name = 'fdipzone';  
name = localStorage.name;  
  
localStorage['name'] = 'fdipzone';  
name = localStorage['name'];  
  
localStorage.setItem('name', 'fdipzone');  
name = localStorage.getItem('name'); 

localStorage[key] = value寫法主流瀏覽器都支持,官方並沒有說明那一種寫法是標准。但如果執行以下的代碼就使localStorage失效。

 

localStorage.setItem = null;  
localStorage.getItem = null;  
localStorage.removeItem = null;  
localStorage.clear = null; 

 

因此,建議使用setItem(), getItem(), removeItem(), clear()來實現寫入,讀取,刪除,清空。

4.如果要保存非字符串的內容,建議使用JSON來處理。寫入數據時用JSON.stringify轉成字符串,讀取數據時用JSON.parse把字符串轉為之前的格式。

例子1:

 

    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">  
    <html>  
     <head>  
      <meta http-equiv="content-type" content="text/html; charset=utf-8">  
      <title> Local Storage and Session Storage </title>  
     </head>  
      
     <body>  
      <p>姓名:<input type="text" name="name" id="name"></p>  
      <p>性別:<input type="radio" name="gender" id="gender1" value="1"> 男 <input type="radio" name="gender" id="gender2" value="2"> 女</p>  
      <p><input type="button" id="saveBtn" value="save"> <input type="button" id="getBtn" value="get"> <input type="button" id="removeBtn" value="remove name"> <input type="button" id="clearBtn" value="clear"> </p>  
      
      <script type="text/javascript">  
        var oStorage = window.localStorage;  
      
        function $(id){  
            return document.getElementById(id);  
        }  
      
        // 保存數據  
        $('saveBtn').onclick = function(){  
            oStorage.setItem('name', $('name').value);  
      
            if($('gender1').checked==true){  
                oStorage.setItem('gender', 1);  
            }else if($('gender2').checked==true){  
                oStorage.setItem('gender', 2);  
            }  
        }  
      
        // 獲取數據  
        $('getBtn').onclick = function(){  
            $('name').value = oStorage.getItem('name');  
            if(oStorage.getItem('gender')==1){  
                $('gender1').checked = true;  
            }else if(oStorage.getItem('gender')==2){  
                $('gender2').checked = true;  
            }  
        }  
      
        // 刪除數據name  
        $('removeBtn').onclick = function(){  
            oStorage.removeItem('name');  
        }  
      
        // 清空數據  
        $('clearBtn').onclick = function(){  
            oStorage.clear();  
        }  
      
      </script>  
      
     </body>  
    </html>  

例子2:使用 JSON.stringify 和 JSON.parse 封裝數據

 

    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">  
    <html>  
     <head>  
      <meta http-equiv="content-type" content="text/html; charset=utf-8">  
      <title> Local Storage and Session Storage </title>  
     </head>  
      
     <body>  
      <p>姓名:<input type="text" name="name" id="name"></p>  
      <p>性別:<input type="radio" name="gender" id="gender1" value="1"> 男 <input type="radio" name="gender" id="gender2" value="2"> 女</p>  
      <p><input type="button" id="saveBtn" value="save"> <input type="button" id="getBtn" value="get"> <input type="button" id="clearBtn" value="clear"> </p>  
      
      <script type="text/javascript">  
        var oStorage = window.localStorage;  
      
        function $(id){  
            return document.getElementById(id);  
        }  
      
        // 保存數據  
        $('saveBtn').onclick = function(){  
            var name = $('name').value;  
            var gender;  
            if($('gender1').checked==true){  
                gender = 1;  
            }else if($('gender2').checked==true){  
                gender = 2;  
            }  
      
            var data = {};  
            data['name'] = name;  
            data['gender'] = gender;  
      
            oStorage.setItem('data', JSON.stringify(data));  
        }  
      
        // 獲取數據  
        $('getBtn').onclick = function(){  
            var data = JSON.parse(oStorage.getItem('data'));  
      
            if(data){  
                var name = data['name'];  
                var gender = data['gender'];  
      
                $('name').value = name;  
      
                if(gender==1){  
                    $('gender1').checked = true;  
                }else if(gender==2){  
                    $('gender2').checked = true;  
                }  
            }  
        }  
      
        // 清空數據  
        $('clearBtn').onclick = function(){  
            oStorage.clear();  
        }  
      
      </script>  
      
     </body>  
    </html>  

 

監聽localStorage的值,當發生變化時同步頁面數據
當調用setItem(), removeItem(), clear() 時,可以監聽這些事件,方便不同的頁面之間更新數據。

 

    // 監聽數據變化,當數據發生變化時,同步數據顯示  
    window.onstorage = function(event){  
        var status = {}  
        status.key = event.key;  
        status.oldValue = event.oldValue;  
        status.newValue = event.newValue;  
        status.url = event.url;  
        status.storage = event.storageArea;  
      
        // 執行同步數據處理...  
    }  

 

頁面數據同步例子:

localStorage1.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
  <meta http-equiv="content-type" content="text/html; charset=utf-8">
  <title> Local Storage and Session Storage </title>
 </head>

 <body>
  <p>姓名:<input type="text" name="name" id="name"></p>
  <p>性別:<input type="radio" name="gender" id="gender1" value="1"> 男 <input type="radio" name="gender" id="gender2" value="2"> 女</p>
  <p><input type="button" id="saveBtn" value="save"> <input type="button" id="getBtn" value="get"> <input type="button" id="clearBtn" value="clear"> </p>

  <script type="text/javascript">
    var oStorage = window.localStorage;

    function $(id){
        return document.getElementById(id);
    }

    // 保存數據
    $('saveBtn').onclick = function(){
        var name = $('name').value;
        var gender;
        if($('gender1').checked==true){
            gender = 1;
        }else if($('gender2').checked==true){
            gender = 2;
        }

        var data = {};
        data['name'] = name;
        data['gender'] = gender;

        oStorage.setItem('data', JSON.stringify(data));
    }

    // 獲取數據
    $('getBtn').onclick = function(){
        getStorageItem();
    }


    // 獲取數據
    function getStorageItem(){
        var data = JSON.parse(oStorage.getItem('data'));
        var name,gender;

        if(data){
            name = data['name'];
            gender = data['gender'];
        }else{
            name = '';
            gender = 0;
        }

        $('name').value = name;

        if(gender==1){
            $('gender1').checked = true;
        }else if(gender==2){
            $('gender2').checked = true;
        }else{
            $('gender1').checked = false;
            $('gender2').checked = false;
        }
    }


    // 清空數據
    $('clearBtn').onclick = function(){
        oStorage.clear();
        $('name').value = '';
        $('gender1').checked = false;
        $('gender2').checked = false;
    }

    // 監聽數據變化,當數據發生變化時,同步數據顯示
    window.onstorage = function(event){
        var status = {}
        status.key = event.key;
        status.oldValue = event.oldValue;
        status.newValue = event.newValue;
        status.url = event.url;
        status.storage = event.storageArea;

        getStorageItem(); // 數據發生變化時,重新獲取數據
    }

  </script>

 </body>
</html>

localStorage2.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
  <meta http-equiv="content-type" content="text/html; charset=utf-8">
  <title> Local Storage and Session Storage </title>
 </head>

 <body>
  <p>姓名:<input type="text" name="name" id="name"></p>
  <p>性別:<input type="radio" name="gender" id="gender1" value="1"> 男 <input type="radio" name="gender" id="gender2" value="2"> 女</p>
  <p><input type="button" id="saveBtn" value="save"> <input type="button" id="getBtn" value="get"> <input type="button" id="clearBtn" value="clear"> </p>

  <script type="text/javascript">
    var oStorage = window.localStorage;

    function $(id){
        return document.getElementById(id);
    }

    // 保存數據
    $('saveBtn').onclick = function(){
        var name = $('name').value;
        var gender;
        if($('gender1').checked==true){
            gender = 1;
        }else if($('gender2').checked==true){
            gender = 2;
        }

        var data = {};
        data['name'] = name;
        data['gender'] = gender;

        oStorage.setItem('data', JSON.stringify(data));
    }

    // 獲取數據
    $('getBtn').onclick = function(){
        getStorageItem();
    }


    // 獲取數據
    function getStorageItem(){
        var data = JSON.parse(oStorage.getItem('data'));
        var name,gender;

        if(data){
            name = data['name'];
            gender = data['gender'];
        }else{
            name = '';
            gender = 0;
        }

        $('name').value = name;

        if(gender==1){
            $('gender1').checked = true;
        }else if(gender==2){
            $('gender2').checked = true;
        }else{
            $('gender1').checked = false;
            $('gender2').checked = false;
        }
    }


    // 清空數據
    $('clearBtn').onclick = function(){
        oStorage.clear();
        $('name').value = '';
        $('gender1').checked = false;
        $('gender2').checked = false;
    }

    // 監聽數據變化,當數據發生變化時,同步數據顯示
    window.onstorage = function(event){
        var status = {}
        status.key = event.key;
        status.oldValue = event.oldValue;
        status.newValue = event.newValue;
        status.url = event.url;
        status.storage = event.storageArea;

        getStorageItem(); // 數據發生變化時,重新獲取數據
    }

  </script>

 </body>
</html>

localstorage3.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
  <meta http-equiv="content-type" content="text/html; charset=utf-8">
  <title> Local Storage and Session Storage </title>
 </head>

 <body>
  <p>姓名:<input type="text" name="name" id="name"></p>
  <p>性別:<input type="radio" name="gender" id="gender1" value="1"> 男 <input type="radio" name="gender" id="gender2" value="2"> 女</p>
  <p><input type="button" id="saveBtn" value="save"> <input type="button" id="getBtn" value="get"> <input type="button" id="clearBtn" value="clear"> </p>

  <script type="text/javascript">
    var oStorage = window.localStorage;

    function $(id){
        return document.getElementById(id);
    }

    // 保存數據
    $('saveBtn').onclick = function(){
        var name = $('name').value;
        var gender;
        if($('gender1').checked==true){
            gender = 1;
        }else if($('gender2').checked==true){
            gender = 2;
        }

        var data = {};
        data['name'] = name;
        data['gender'] = gender;

        oStorage.setItem('data', JSON.stringify(data));
    }

    // 獲取數據
    $('getBtn').onclick = function(){
        getStorageItem();
    }


    // 獲取數據
    function getStorageItem(){
        var data = JSON.parse(oStorage.getItem('data'));
        var name,gender;

        if(data){
            name = data['name'];
            gender = data['gender'];
        }else{
            name = '';
            gender = 0;
        }

        $('name').value = name;

        if(gender==1){
            $('gender1').checked = true;
        }else if(gender==2){
            $('gender2').checked = true;
        }else{
            $('gender1').checked = false;
            $('gender2').checked = false;
        }
    }


    // 清空數據
    $('clearBtn').onclick = function(){
        oStorage.clear();
        $('name').value = '';
        $('gender1').checked = false;
        $('gender2').checked = false;
    }

    // 監聽數據變化,當數據發生變化時,同步數據顯示
    window.onstorage = function(event){
        var status = {}
        status.key = event.key;
        status.oldValue = event.oldValue;
        status.newValue = event.newValue;
        status.url = event.url;
        status.storage = event.storageArea;

        getStorageItem(); // 數據發生變化時,重新獲取數據
    }

  </script>

 </body>
</html>

點擊下載查看

轉載:http://blog.csdn.net/fdipzone/article/details/25517615

參考:http://www.smashingmagazine.com/2010/10/local-storage-and-how-to-use-it/

HTML5 Web Storage用法參考:

http://justcoding.iteye.com/blog/2092992

HTML5 本地存儲參考

http://www.cnblogs.com/rainman/archive/2011/06/22/2086069.html


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