[HTML] 纯文本查看 复制代码
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
</head>
<body>
<button class="set">存储</button>
<button class="get">读取</button>
<button class="remove">删除</button>
<iframe src="http://localhost:8000/storage.html"></iframe> //嵌入【B域】的一个空页面
</body>
<script src="js/localStorage.js"></script>
</html>
[JavaScript] 纯文本查看 复制代码
/*这段代码是用来测试localStorage中字符串的编码格式*/
/**
* 计算字符串所占的内存字节数，默认使用UTF-8的编码方式计算，也可制定为UTF-16
* UTF-8 是一种可变长度的 Unicode 编码格式，使用一至四个字节为每个字符编码
*
* 000000 - 00007F(128个代码) 0zzzzzzz(00-7F) 一个字节
* 000080 - 0007FF(1920个代码) 110yyyyy(C0-DF) 10zzzzzz(80-BF) 两个字节
* 000800 - 00D7FF
00E000 - 00FFFF(61440个代码) 1110xxxx(E0-EF) 10yyyyyy 10zzzzzz 三个字节
* 010000 - 10FFFF(1048576个代码) 11110www(F0-F7) 10xxxxxx 10yyyyyy 10zzzzzz 四个字节
*
* 注: Unicode在范围 D800-DFFF 中不存在任何字符
*
* UTF-16 大部分使用两个字节编码，编码超出 65535 的使用四个字节
* 000000 - 00FFFF 两个字节
* 010000 - 10FFFF 四个字节
*
* @param {String} str
* @param {String} charset utf-8, utf-16
* @return {Number}
*/
function sizeof(str,charset){
var strCode=0,charCode;
charset = charset?charset.toLowerCase():'';
if(charset=='utf-16'||charset=='utf16'){
for(var i=0,len=str.length;i<len;i++){
charCode = str.charCodeAt(i);
strCode += charCode<0xffff?2:4;
}
}else{
for(var i=0,len=str.length;i<len;i++){
charCode = str.charCodeAt(i);
strCode += (charCode<0x007f&&1)||(charCode<0x07ff&&2)||(charCode<0xffff&&3)||4;
}
}
return strCode/1024/1024/2;
}
/*测试localStorage中字符串的编码格式结束*/
function storage(type,key,value){
var val = localStorage.getItem(key);
switch (type){
case 'get':
if(val){
return val;
}else{
return window.frames[0].postMessage(JSON.stringify({type:type,key:key}),'http://localhost:8000');
}
break;
case 'set':
if(!val&&sizeofLocal()+sizeof(value)>5){
window.frames[0].postMessage(JSON.stringify({type:type,key:key,value:value}),'http://localhost:8000');
}else{
localStorage.setItem(key,value);
}
break;
case 'remove':
if(val){
localStorage.removeItem(key);
}else{
window.frames[0].postMessage(JSON.stringify({type:type,key:key}),'http://localhost:8000');
}
break;
default:
break;
}
}
function sizeofLocal(){
var myStr = '',charCode,strCode=0;
for(item in localStorage){
if(localStorage.hasOwnProperty(item)){
myStr += localStorage.getItem(item);
}
}
for(var i=0,len=myStr.length;i<len;i++){
charCode = myStr.charCodeAt(i);
strCode += charCode<0xffff?2:4;
}
return strCode/1024/1024/2;
}
var myStr='';
for(var i=0;i<1024*1200;i++){
myStr += 1+'12'+'啦';
}
document.querySelector(".set").onclick = function(){
storage("set","yoyo",myStr);
}
document.querySelector(".get").onclick = function(){
storage("get","yoyo");
window.addEventListener('message',function(e){
window.myStorage = e.data;
})
}
document.querySelector(".remove").onclick = function(){
storage("remove","yoyo");
}
[HTML] 纯文本查看 复制代码
storage.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
</head>
<body>
</body>
<script type="text/javascript">
var fn = function(){};
fn.prototype = {
setLocal:function(key,value){
localStorage.setItem(key,value);
},
getLocal:function(key){
return localStorage.getItem(key);
},
removeLocal:function(key){
localStorage.removeItem(key);
},
bindEvent:function(){
var self = this;
//监听
window.addEventListener('message',function(e){
if(window.parent!=e.source) return;
var option = JSON.parse(e.data);
if(option.type.toLowerCase()=="get"){
var data = self.getLocal(option.key);
window.parent.postMessage(data,'*');
}
option.type.toLowerCase()=="set"&&self.setLocal(option.key,option.value);
option.type.toLowerCase()=="remove"&&self.removeLocal(option.key);
})
},
init:function(){
var self = this;
self.bindEvent();
}
}
var tools = new fn();
tools.init();
</script>
