字符串加密的代码

总觉得第19行可以用var keyCoded = pkey.charCodeAt(pkey.length-1)代替
 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="utf-8">
 5     <title>CALL语句</title>
 6 
 7     <script lang="javascript">
 8         var msgCoded;
 9         var msgEncoded;
10 
11         function CodeAndEncode(pkey, date)
12         {
13             var codeStr = "";
14             for (i in date)
15             {
16                 var dateCoded;
17                 for (j in pkey)
18                 {
19                     var keyCoded = pkey.charCodeAt(j);
20                     var dateCoded = date.charCodeAt(i) ^ keyCoded;
21                 }
22                 codeStr += String.fromCharCode(dateCoded);
23             }
24             return codeStr;
25         }
26         function BtnCode_onclick()
27         {
28             var date = TextArea1.value;
29             var key = Password1.value;
30             msgCoded = CodeAndEncode(key, date);
31             TextArea1.value = msgCoded;
32         }
33         function BtnEncode_onclick()
34         {
35             var date = TextArea1.value;
36             var key = Password1.value;
37             msgEncoded = CodeAndEncode(key, date);
38             TextArea1.value = msgEncoded;
39         }
40     </script>
41 </head>
42 <body>
43     <textarea id="TextArea1" style="331px; height:211px"></textarea>
44     &nbsp<br/>
45     密钥：&nbsp;
46     <input id="Password1" type="password" />&nbsp;
47     <input id="BtnCode" type="button" value="加密" onclick="BtnCode_onclick()"
48            style="57px" />
49     <input id="BtnEnCode" type="button" value="解密" onclick="BtnEncode_onclick()"
50            style="55px" />
51 
52 </body>
53 </html>