HTML5本地存储之Web Storage篇
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:
1.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;
2.根据手机号码,查找机主;
3.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:
[html]
01.!DOCTYPE HTML>
02.html>
03.head>
04. meta charset="utf-8"/>
05. title>
HTML5本地存储之Web Storage篇/title>
06./head>
07.body>
08. p style="border: 2px dashed #ccc;
width:320px;
text-align:center;
">
09. label for="user_name">
姓名:/label>
10. input type="text" id="user_name" name="user_name" class="text"/>
11. br/>
12. label for="mobilephone">
手机:/label>
13. input type="text" id="mobilephone" name="mobilephone"/>
14. br/>
15. input type="button" onclick="save()" value="新增记录"/>
16. hr/>
17. label for="seArch_phone">
输入手机号:/label>
18. input type="text" id="search_phone" name="search_phone"/>
19. input type="button" onclick="find()" value="查找机主"/>
20. p id="find_result">
br/>
/p>
21. /p>
22. br/>
23. p id="list">
24. /p>
25./body>
26./html>
!DOCTYPE HTML>
html>
head>
meta charset="utf-8"/>
title>
HTML5本地存储之Web Storage篇/title>
/head>
body>
p 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>
/p>
br/>
p id="list">
/p>
/body>
/html>
界面展现如下:
要实现联系人的保存,只需要简单实现如下JS方法即可:
[javascript]
01.//保存数据
02.function save(){
03. VAR mobilephone = document.getElementById("mobilephone").value;
04. var user_name = document.getElementById("user_name").value;
05. localStorage.setItem(mobilephone,user_name);
06.}
//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);
}
要实现查找机主,则实现如下JS方法:
[javascript]
01.//查找数据
02.function find(){
03. var search_phone = document.getElementById("search_phone").value;
04. var name = localStorage.getItem(search_phone);
05. var find_result = document.getElementById("find_result");
06. find_result.innerHTML = search_phone + "的机主是:" + name;
07.}
//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:
[javascript]
01.//将所有存储在localStorage中的对象提取出来,并展现到界面上
02.function loadAll(){
03. var list = document.getElementById("list");
04. if(localStorage.length>
0){
05. var result = "table border='1'>
";
06. result += "tr>
td>
姓名/td>
td>
手机号码/td>
/tr>
";
07. for(var i=0;
ilocalStorage.length;
i++){
08. var mobilephone = localStorage.key(i);
09. var name = localStorage.getItem(mobilephone);
10. result += "tr>
td>
"+name+"/td>
td>
"+mobilephone+"/td>
/tr>
";
11. }
12. result += "/table>
";
13. list.innerHTML = result;
14. }
else{
15. list.innerHTML = "目前数据为空,赶紧开始加入联系人吧";
16. }
17.}
//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;
ilocalStorage.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";
}
}
问题:如上的演示,都只有2个字段,姓名和手机号码,如果要存入更为丰富的联系人信息,比如公司名称、家庭地址等,如何实现呢?Web Storage不是只能处理字符串吗?此时,可以利用JSON的stringify()方法,将复杂对象转变成字符串,存入Web Storage中;当从Web Storage中读取时,可以通过JSON的parse()方法再转换成JSON对象;
如下简单演示增加了公司属性的联系人保存JS代码:
[javascript]
01.//保存数据
02.function save(){
03. var contact = new Object;
04. contact.user_name = document.getElementById("user_name").value;
05. contact.mobilephone = document.getElementById("mobilephone").value;
06. contact.COMpany = document.getElementById("company").value;
07. var str = JSON.stringify(contact);
08. localStorage.setItem(contact.mobilephone,str);
09. loadAll();
10.}
11.//将所有存储在localStorage中的对象提取出来,并展现到界面上
12.function loadAll(){
13. var list = document.getElementById("list");
14. if(localStorage.length>
0){
15. var result = "table border='1'>
";
16. result += "tr>
td>
姓名/td>
td>
手机/td>
td>
公司/td>
/tr>
";
17. for(var i=0;
ilocalStorage.length;
i++){
18. var mobilephone = localStorage.key(i);
19. var str = localStorage.getItem(mobilephone);
20. var contact = JSON.parse(str);
21. result += "tr>
td>
"+contact.user_name+"/td>
td>
"+contact.mobilephone+"/td>
td>
"+contact.company+"/td>
/tr>
";
22. }
23. result += "/table>
";
24. list.innerHTML = result;
25. }
else{
26. list.innerHTML = "目前数据为空,赶紧开始加入联系人吧";
27. }
28.}
//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;
ilocalStorage.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";
}
}
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:
1.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;
2.根据手机号码,查找机主;
3.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:
[html]
01.!DOCTYPE HTML>
02.html>
03.head>
04. meta charset="utf-8"/>
05. title>
HTML5本地存储之Web Storage篇/title>
06./head>
07.body>
08. p style="border: 2px dashed #ccc;
width:320px;
text-align:center;
">
09. label for="user_name">
姓名:/label>
10. input type="text" id="user_name" name="user_name" class="text"/>
11. br/>
12. label for="mobilephone">
手机:/label>
13. input type="text" id="mobilephone" name="mobilephone"/>
14. br/>
15. input type="button" onclick="save()" value="新增记录"/>
16. hr/>
17. label for="search_phone">
输入手机号:/label>
18. input type="text" id="search_phone" name="search_phone"/>
19. input type="button" onclick="find()" value="查找机主"/>
20. p id="find_result">
br/>
/p>
21. /p>
22. br/>
23. p id="list">
24. /p>
25./body>
26./html>
!DOCTYPE HTML>
html>
head>
meta charset="utf-8"/>
title>
HTML5本地存储之Web Storage篇/title>
/head>
body>
p 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>
/p>
br/>
p id="list">
/p>
/body>
/html>
界面展现如下:
要实现联系人的保存,只需要简单实现如下JS方法即可:
[javascript]
01.//保存数据
02.function save(){
03. var mobilephone = document.getElementById("mobilephone").value;
04. var user_name = document.getElementById("user_name").value;
05. localStorage.setItem(mobilephone,user_name);
06.}
//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);
}
要实现查找机主,则实现如下JS方法:
[javascript]
01.//查找数据
02.function find(){
03. var search_phone = document.getElementById("search_phone").value;
04. var name = localStorage.getItem(search_phone);
05. var find_result = document.getElementById("find_result");
06. find_result.innerHTML = search_phone + "的机主是:" + name;
07.}
//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:
[javascript]
01.//将所有存储在localStorage中的对象提取出来,并展现到界面上
02.function loadAll(){
03. var list = document.getElementById("list");
04. if(localStorage.length>
0){
05. var result = "table border='1'>
";
06. result += "tr>
td>
姓名/td>
td>
手机号码/td>
/tr>
";
07. for(var i=0;
ilocalStorage.length;
i++){
08. var mobilephone = localStorage.key(i);
09. var name = localStorage.getItem(mobilephone);
10. result += "tr>
td>
"+name+"/td>
td>
"+mobilephone+"/td>
/tr>
";
11. }
12. result += "/table>
";
13. list.innerHTML = result;
14. }
else{
15. list.innerHTML = "目前数据为空,赶紧开始加入联系人吧";
16. }
17.}
//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;
ilocalStorage.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";
}
}
问题:如上的演示,都只有2个字段,姓名和手机号码,如果要存入更为丰富的联系人信息,比如公司名称、家庭地址等,如何实现呢?Web Storage不是只能处理字符串吗?此时,可以利用JSON的stringify()方法,将复杂对象转变成字符串,存入Web Storage中;当从Web Storage中读取时,可以通过JSON的parse()方法再转换成JSON对象;
如下简单演示增加了公司属性的联系人保存JS代码:
[javascript]
01.//保存数据
02.function save(){
03. var contact = new Object;
04. contact.user_name = document.getElementById("user_name").value;
05. contact.mobilephone = document.getElementById("mobilephone").value;
06. contact.company = document.getElementById("company").value;
07. var str = JSON.stringify(contact);
08. localStorage.setItem(contact.mobilephone,str);
09. loadAll();
10.}
11.//将所有存储在localStorage中的对象提取出来,并展现到界面上
12.function loadAll(){
13. var list = document.getElementById("list");
14. if(localStorage.length>
0){
15. var result = "table border='1'>
";
16. result += "tr>
td>
姓名/td>
td>
手机/td>
td>
公司/td>
/tr>
";
17. for(var i=0;
ilocalStorage.length;
i++){
18. var mobilephone = localStorage.key(i);
19. var str = localStorage.getItem(mobilephone);
20. var contact = JSON.parse(str);
21. result += "tr>
td>
"+contact.user_name+"/td>
td>
"+contact.mobilephone+"/td>
td>
"+contact.company+"/td>
/tr>
";
22. }
23. result += "/table>
";
24. list.innerHTML = result;
25. }
else{
26. list.innerHTML = "目前数据为空,赶紧开始加入联系人吧";
27. }
28.}
//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;
ilocalStorage.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";
}
}
觉得可用,就经常来吧! 欢迎评论哦! html5教程,巧夺天工,精雕玉琢。小宝典献丑了!
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