HTML5本地存储之Web Storage篇
查看次数218995 发表时间2013-01-23 14:30:52
Web Storage是HTML5引入的一个非常重要的功能,可以在客户端本地存储数据,类似HTML4的cookie,但可实现功能要比cookie强大的多,cookie大小被限制在4KB,Web Storage官方建议为每个网站5MB。Web Storage又分为... |
Web Storage是HTML5引入的一个非常重要的功能,可以在客户端本地存储数据,类似HTML4的cookie,但可实现功能要比cookie强大的多,cookie大小被限制在4KB,Web Storage官方建议为每个网站5MB。
Web Storage又分为两种:
- sessionStorage
- localStorage
从字面意思就可以很清楚的看出来,sessionStorage将数据保存在session中,浏览器关闭也就没了;而localStorage则一直将数据保存在客户端本地;
不管是sessionStorage,还是localStorage,可使用的API都相同,常用的有如下几个(以localStorage为例):
- 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);
如上,key和value都必须为字符串,换言之,web Storage的API只能操作字符串。
接下来,我们通过Web Storage开发一个简单的通讯录小程序,以演示相关API的使用方法;我们要实现如下功能:
- 录入联系人,联系人有姓名、手机号码2个字段,以手机号作为key存入localStorage;
- 根据手机号码,查找机主;
- 列出当前已保存的所有联系人信息;
首先,准备一个简单的HTML页面,如下:
- <!DOCTYPE HTML>
- <html>
- <head>
- <meta charset="utf-8"/>
- <title>HTML5本地存储之Web Storage篇</title>
- </head>
- <body>
- <div style="border: 2px dashed #ccc;width:320px;text-align:center;">
- <label for="user_name">姓名:</label>
- <input type="text" id="user_name" name="user_name" class="text"/>
- <br/>
- <label for="mobilephone">手机:</label>
- <input type="text" id="mobilephone" name="mobilephone"/>
- <br/>
- <input type="button" onclick="save()" value="新增记录"/>
- <hr/>
- <label for="search_phone">输入手机号:</label>
- <input type="text" id="search_phone" name="search_phone"/>
- <input type="button" onclick="find()" value="查找机主"/>
- <p id="find_result"><br/></p>
- </div>
- <br/>
- <div id="list">
- </div>
- </body>
- </html>
<!DOCTYPE HTML> <html> <head> <meta charset="utf-8"/> <title>HTML5本地存储之Web Storage篇</title> </head> <body> <div style="border: 2px dashed #ccc;width:320px;text-align:center;"> <label for="user_name">姓名:</label> <input type="text" id="user_name" name="user_name" class="text"/> <br/> <label for="mobilephone">手机:</label> <input type="text" id="mobilephone" name="mobilephone"/> <br/> <input type="button" onclick="save()" value="新增记录"/> <hr/> <label for="search_phone">输入手机号:</label> <input type="text" id="search_phone" name="search_phone"/> <input type="button" onclick="find()" value="查找机主"/> <p id="find_result"><br/></p> </div> <br/> <div id="list"> </div> </body> </html>
要实现联系人的保存,只需要简单实现如下JS方法即可:
- //保存数据
- function save(){
- var mobilephone = document.getElementById("mobilephone").value;
- var user_name = document.getElementById("user_name").value;
- localStorage.setItem(mobilephone,user_name);
- }
//保存数据 function save(){ var mobilephone = document.getElementById("mobilephone").value; var user_name = document.getElementById("user_name").value; localStorage.setItem(mobilephone,user_name); }
- //查找数据
- function find(){
- var search_phone = document.getElementById("search_phone").value;
- var name = localStorage.getItem(search_phone);
- var find_result = document.getElementById("find_result");
- find_result.innerHTML = search_phone + "的机主是:" + name;
- }
//查找数据 function find(){ var search_phone = document.getElementById("search_phone").value; var name = localStorage.getItem(search_phone); var find_result = document.getElementById("find_result"); find_result.innerHTML = search_phone + "的机主是:" + name; }
要展现所有已保存的联系人信息,则需要使用localStorage.key(index)方法,如下:
- //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='1'>";
- result += "<tr><td>姓名</td><td>手机号码</td></tr>";
- for(var i=0;i<localStorage.length;i++){
- var mobilephone = localStorage.key(i);
- var name = localStorage.getItem(mobilephone);
- result += "<tr><td>"+name+"</td><td>"+mobilephone+"</td></tr>";
- }
- result += "</table>";
- list.innerHTML = result;
- }else{
- list.innerHTML = "目前数据为空,赶紧开始加入联系人吧";
- }
- }
//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='1'>"; result += "<tr><td>姓名</td><td>手机号码</td></tr>"; for(var i=0;i<localStorage.length;i++){ var mobilephone = localStorage.key(i); var name = localStorage.getItem(mobilephone); result += "<tr><td>"+name+"</td><td>"+mobilephone+"</td></tr>"; } result += "</table>"; list.innerHTML = result; }else{ list.innerHTML = "目前数据为空,赶紧开始加入联系人吧"; } }
如下简单演示增加了公司属性的联系人保存JS代码:
- //保存数据
- function save(){
- var contact = new Object;
- contact.user_name = document.getElementById("user_name").value;
- contact.mobilephone = document.getElementById("mobilephone").value;
- contact.company = document.getElementById("company").value;
- var str = JSON.stringify(contact);
- localStorage.setItem(contact.mobilephone,str);
- loadAll();
- }
- //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='1'>";
- result += "<tr><td>姓名</td><td>手机</td><td>公司</td></tr>";
- for(var i=0;i<localStorage.length;i++){
- var mobilephone = localStorage.key(i);
- var str = localStorage.getItem(mobilephone);
- var contact = JSON.parse(str);
- result += "<tr><td>"+contact.user_name+"</td><td>"+contact.mobilephone+"</td><td>"+contact.company+"</td></tr>";
- }
- result += "</table>";
- list.innerHTML = result;
- }else{
- list.innerHTML = "目前数据为空,赶紧开始加入联系人吧";
- }
- }
//保存数据 function save(){ var contact = new Object; contact.user_name = document.getElementById("user_name").value; contact.mobilephone = document.getElementById("mobilephone").value; contact.company = document.getElementById("company").value; var str = JSON.stringify(contact); localStorage.setItem(contact.mobilephone,str); loadAll(); } //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='1'>"; result += "<tr><td>姓名</td><td>手机</td><td>公司</td></tr>"; for(var i=0;i<localStorage.length;i++){ var mobilephone = localStorage.key(i); var str = localStorage.getItem(mobilephone); var contact = JSON.parse(str); result += "<tr><td>"+contact.user_name+"</td><td>"+contact.mobilephone+"</td><td>"+contact.company+"</td></tr>"; } result += "</table>"; list.innerHTML = result; }else{ list.innerHTML = "目前数据为空,赶紧开始加入联系人吧"; } }
(转发请注明转自:学PHP)
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