javascript eval加密和解密源码

    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">  
    <html xmlns="http://www.w3.org/1999/xhtml">  
    <head>  
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />  
    <title>eval解密/加密在线工具</title>  
    <script>   
    a=62;   
    function encode() {    //加密  
     var code = document.getElementById('code').value;   
     code = code.replace(/[rn]+/g, '');   
     code = code.replace(/'/g, "\'");   
     var tmp = code.match(/b(w+)b/g);   
     tmp.sort();   
     var dict = [];   
     var i, t = '';   
     for(var i=0; i<tmp.length; i++) {   
       if(tmp[i] != t) dict.push(t = tmp[i]);   
     }   
     var len = dict.length;   
     var ch;   
     for(i=0; i<len; i++) {   
       ch = num(i);   
       code = code.replace(new RegExp('\b'+dict[i]+'\b','g'), ch);   
       if(ch == dict[i]) dict[i] = '';   
     }   
     document.getElementById('code').value = "eval(function(p,a,c,k,e,d){e=function(c){return(c<a?'':e(parseInt(c/a)))+((c=c%a)>35?String.fromCharCode(c+29):c.toString(36))};if(!''.replace(/^/,String)){while(c--)d[e(c)]=k[c]||e(c);k=[function(e){return d[e]}];e=function(){return'\\w+'};c=1};while(c--)if(k[c])p=p.replace(new RegExp('\\b'+e(c)+'\\b','g'),k[c]);return p}("   
       + "'"+code+"',"+a+","+len+",'"+ dict.join('|')+"'.split('|'),0,{}))";   
    }   
    function num(c) {   
     return(c<a?'':num(parseInt(c/a)))+((c=c%a)>35?String.fromCharCode(c+29):c.toString(36));   
    }   
    function run() {   
     eval(document.getElementById('code').value);   
    }   
    function decode() {    //解密  
     var code = document.getElementById('code').value;   
     code = code.replace(/^eval/, '');   
     document.getElementById('code').value = eval(code);   
    }   
    </script>   
    <textarea id=code cols=80 rows=20>   
    </textarea><br>   
    <input type=button onclick=encode() value=加密>   
    <input type=button onclick=decode() value=解密>