How to use HTML5-Web storage?

Web storage, a better local storage method than cookies

localStorage and sessionStorage

　localStorage-data storage without time limit

　sessionStorage-data storage for a session

//是否支持if(typeof(Storage)!=="undefined")
{// 是的! 支持 localStorage  sessionStorage 对象!// 一些代码.....} else {// 抱歉! 不支持 web 存储。}

localStorage object

There is no time limit for the data stored in the localStorage object

localStorage.sitename="小南瓜";
document.getElementById("result").innerHTML="网站名：" + localStorage.sitename;

Whether it is localStorage or sessionStorage, the APIs that can be used are the same, and the commonly used ones are as follows (localStorage For example):

保存数据：localStorage.setItem(key,value);
读取数据：localStorage.getItem(key);
删除单个数据：localStorage.removeItem(key);
删除所有数据：localStorage.clear();
得到某个索引的key：localStorage.key(index);

Tips: Key/value pairs are usually stored as strings, and you can convert this format according to your needs.

if(typeof(Storage)!=="undefined")
{
　　if (localStorage.clickcount)
　　{
　　localStorage.clickcount=Number(localStorage.clickcount)+1;
　　}
　　else
　　{
　　localStorage.clickcount=1;
　　}
　　document.getElementById("result").innerHTML=" 你已经点击了按钮 " + localStorage.clickcount + " 次 ";
}
else
{
document.getElementById("result").innerHTML="对不起，您的浏览器不支持 web 存储。";
}

sessionStorage object

sessionStorage stores data for a session. The data will be deleted when the user closes the browser window

　　 if(typeof(Storage)!=="undefined")
    {
        if (sessionStorage.clickcount)
        {
            sessionStorage.clickcount=Number(sessionStorage.clickcount)+1;
        }
        else
        {
            sessionStorage.clickcount=1;
        }
        document.getElementById("result").innerHTML="在这个会话中你已经点击了该按钮 " + sessionStorage.clickcount + " 次 ";
    }
    else
    {
        document.getElementById("result").innerHTML="抱歉，您的浏览器不支持 web 存储";
    }

Simple website list program

 <div style="border: 2px dashed #ccc;width:320px;text-align:center;">     <label for="sitename">网站名(key)：</label>  <input type="text" id="sitename" name="sitename" class="text"/>  <br/>  <label for="siteurl">网 址(value)：</label>  <input type="text" id="siteurl" name="siteurl"/>  <br/>  <input type="button" onclick="save()" value="新增记录"/>  <hr/>  <label for="search_phone">输入网站名：</label>  <input type="text" id="search_site" name="search_site"/>  <input type="button" onclick="find()" value="查找网站"/>  <p id="find_result"><br/></p>  </div>  <br/>  <div id="list">  </div>  <script>// 载入所有存储在localStorage的数据    loadAll();     
        //保存数据  function save(){  var siteurl = document.getElementById("siteurl").value;  var sitename = document.getElementById("sitename").value;  
        localStorage.setItem(sitename, siteurl);
        alert("添加成功");
    }//查找数据  function find(){  var search_site = document.getElementById("search_site").value;  var sitename = localStorage.getItem(search_site);  var find_result = document.getElementById("find_result");  
        find_result.innerHTML = search_site + "的网址是：" + sitename;  
    }//将所有存储在localStorage中的对象提取出来，并展现到界面上function loadAll(){  var list = document.getElementById("list");  if(localStorage.length>0){  var result = "<table border=&#39;1&#39;>";  
            result += "<tr><td>网站名</td><td>网址</td></tr>";  for(var i=0;i<localStorage.length;i++){  var sitename = localStorage.key(i);  var siteurl = localStorage.getItem(sitename);  
                result += "<tr><td>"+sitename+"</td><td>"+siteurl+"</td></tr>";  
            }  
            result += "</table>";  
            list.innerHTML = result;  
        }else{  
            list.innerHTML = "数据为空……";  
        }  
    }      </script>

Run Result:

JSON.stringify

##　 Store object data and convert the object to a string

var site = new Object;
...var str = JSON.stringify(site); // 将对象转换为字符串

JSON.parse

Convert the string into a JSON object

 <div style="border: 2px dashed #ccc;width:320px;text-align:center;"><label for="keyname">别名(key):</label>  <input type="text" id="keyname" name="keyname" class="text"/>  <br/>  <label for="sitename">网站名：</label>  <input type="text" id="sitename" name="sitename" class="text"/>  <br/>  <label for="siteurl">网 址：</label>  <input type="text" id="siteurl" name="siteurl"/>  <br/>  <input type="button" onclick="save()" value="新增记录"/>  <hr/>  <label for="search_phone">输入别名(key)：</label>  <input type="text" id="search_site" name="search_site"/>  <input type="button" onclick="find()" value="查找网站"/>  <p id="find_result"><br/></p>  </div>  <br/>  <div id="list">  </div>  <script>//保存数据  function save(){  var site = new Object;
        site.keyname = document.getElementById("keyname").value;
        site.sitename = document.getElementById("sitename").value;  
        site.siteurl = document.getElementById("siteurl").value;var str = JSON.stringify(site); // 将对象转换为字符串        localStorage.setItem(site.keyname,str);  
        alert("保存成功");
    }  //查找数据  function find(){  var search_site = document.getElementById("search_site").value;  var str = localStorage.getItem(search_site);  var find_result = document.getElementById("find_result");var site = JSON.parse(str);  
        find_result.innerHTML = search_site + "的网站名是：" + site.sitename + "，网址是：" + site.siteurl;  
    }  
    //将所有存储在localStorage中的对象提取出来，并展现到界面上// 确保存储的 keyname 对应的值为转换对象，否则JSON.parse会报错function loadAll(){  var list = document.getElementById("list");  if(localStorage.length>0){  var result = "<table border=&#39;1&#39;>";  
            result += "<tr><td>别名</td><td>网站名</td><td>网址</td></tr>";  for(var i=0;i<localStorage.length;i++){ var keyname = localStorage.key(i);  var str = localStorage.getItem(keyname);  var site = JSON.parse(str);  
                result += "<tr><td>"+site.keyname+"</td><td>"+site.sitename+"</td><td>"+site.siteurl+"</td></tr>";  
            }  
            result += "</table>";  
            list.innerHTML = result;  
        }else{  
            list.innerHTML = "数据为空...";  
        }  
    }  </script>

The above is JSON. The result of stringify conversion

The following is the result of JSON.parse conversion

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