JS使用eval进行加密解密

源码

var 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 decode() {
  var code = document.getElementById("code").value;
  code = code.replace(/^eval/, "");
  document.getElementById("code").value = eval(code);
}

function run() {
  eval(document.getElementById("code").value);
}