/** JQuery Html Encoding、Decoding 
* 原理是利用JQuery自带的html()和text()函数可以转义Html字符 
* 虚拟一个Div通过赋值和取值来得到想要的Html编码或者解码 
*/ 
<script src="http://libs.baidu.com/jquery/1.9.0/jquery.js"></script> 
<script type="text/javascript"> 
//Html编码获取Html转义实体 
function htmlEncode(value){ 
 return $('<div/>').text(value).html(); 
} 
//Html解码获取Html实体 
function htmlDecode(value){ 
 return $('<div/>').html(value).text(); 
} 
</script> 

<script type="text/javascript"> 
//获取Html转义字符 
function htmlEncode( html ) { 
 return document.createElement( 'a' ).appendChild( 
  document.createTextNode( html ) ).parentNode.innerHTML; 
}; 
//获取Html 
function htmlDecode( html ) { 
 var a = document.createElement( 'a' ); a.innerHTML = html; 
 return a.textContent; 
}; 
</script> 

//编码 
 function html_encode(str) 
 { 
 var s = ""; 
 if (str.length == 0) return ""; 
 s = str.replace(/&/g, ">"); 
 s = s.replace(/</g, "<"); 
 s = s.replace(/>/g, ">"); 
 s = s.replace(/ /g, " "); 
 s = s.replace(/\'/g, "'"); 
 s = s.replace(/\"/g, """); 
 s = s.replace(/\n/g, "<br>"); 
 return s; 
 } 
 //解码 
 function html_decode(str) 
 { 
 var s = ""; 
 if (str.length == 0) return ""; 
 s = str.replace(/>/g, "&"); 
 s = s.replace(/</g, "<"); 
 s = s.replace(/>/g, ">"); 
 s = s.replace(/ /g, " "); 
 s = s.replace(/'/g, "\'"); 
 s = s.replace(/"/g, "\""); 
 s = s.replace(/<br>/g, "\n"); 
 return s; 
 }