JavaScript利用密钥加密与解密

<!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>
    <title>JavaScript利用密钥加密与解密</title>
    <script type="text/javascript">
        function getKey() {
            var key = $F("txtKey");
            if (key == "") return 0;
            var result = 0;
            for (var i = 0; i < key.length; i++) {
                result += key.charCodeAt(i) * key.length;               
            }
            return result;
        }
        var fnCompile = function() {
            var result = compile($F('txtInfo'), getKey());
            $("txtInfo").value = result;
        }
        var fnUncompile = function() {
            var result = uncompile($F('txtInfo'), getKey());
            $("txtInfo").value = result;
        }       
        window.onload = function() {
            addEvent($("btnCompile"), "click", fnCompile);
            addEvent($("btnUncompile"), "click", fnUncompile);         
        }

        //加密
        //info:待加密信息,key:密钥
        function compile(info, key) {
            var result = "";
            for (var i = 0; i < info.length; i++) {
                var tempNum = info.charCodeAt(i) + key;
                result += tempNum + ",";
            }
            if (result.substring(result.length - 1, result.length) == ",")
                result = result.substring(0, result.length - 1);
            return escape(result);
        }
        //解密
        //info:待解密信息,key:密钥
        function uncompile(info, key) {
            var result = "";
            var info = unescape(info).split(',');
            for (var i = 0; i < info.length; i++) {
                var tempNum = info[i] - key;
                result += String.fromCharCode(tempNum);
            }
            return result;
        }
       
        function $(id) { return document.getElementById(id); }
        function $F(id) { return document.getElementById(id).value; }
        //绑定事件
        function addEvent(obj, type, fn) {
            if (obj.attachEvent) {
                obj['e' + type + fn] = fn;
                obj[type + fn] = function() { obj['e' + type + fn]

(window.event); }
                obj.attachEvent('on' + type, obj[type + fn]);
            } else obj.addEventListener(type, fn, false);
        }
        //移除事件
        function removeEvent(obj, type, fn) {
            if (obj.detachEvent) {
                obj.detachEvent('on' + type, obj[type + fn]);
                obj[type + fn] = null;
            } else obj.removeEventListener(type, fn, false);
        }

     
    </script>
</head>
<body>
    <form id="form1" runat="server">
    密钥：<input type="text" id="txtKey" value="123" />
    <input type="button" id="btnCompile" value="加密" />
    <input type="button" id="btnUncompile" value="解密" />
   
    <br />
    <textarea id="txtInfo" rows="20" cols="80">想加密的字123...</textarea>
    </form>
</body>
</html>
如下图所示：