JavaScript加密解密

<script>
a=62;
function encode() {
var code = document.getElementById('code').value;
code = code.replace(/[\r\n]+/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() {
var code = document.getElementById('code').value;
code = code.replace(/^eval/, '');
document.getElementById('code').value = eval(code);
}



function encode2() {
var code = document.getElementById('code').value;

var  kode=code;
x='';
for(i=0;i<kode.length;i++){
c=kode.charCodeAt(i)+3;
if(c>128) alert(kode.charAt(i)+"___"+c+"___"+(128-c));
//if(c>128){
//x+="\\\\"+(c-128);

//}else{
x+=String.fromCharCode(c)
//}

}
kode=x



document.getElementById('code').value = "kode=\""+kode.replace(/\"/img,"\\\"").replace(/\r/img,"\\r").replace(/\n/img,"\\n")+"\";"+"x='';for(i=0;i<kode.length;i++){c=kode.charCodeAt(i)-3;if(c<0)c+=128;x+=String.fromCharCode(c)}kode=x";
}
</script>




<textarea id=code cols=80 rows=20>

</textarea>

<input type=button onclick=encode() value=编码>
<input type=button onclick=run() value=执行>
<input type=button onclick=decode() value=解码>
<input type=button onclick=encode2() value=编码2>