要完成此效果需要两个步骤
第一步：把如下代码加入到<head>区域中
<SCRIPT LANGUAGE="JavaScript">
<!-- Begin
function Encrypt(theText) {
output = new String;
Temp = new Array();
Temp2 = new Array();
TextSize = theText.length;
for (i = 0; i < TextSize; i++) {
rnd = Math.round(Math.random() * 122) + 68;
Temp[i] = theText.charCodeAt(i) + rnd;
Temp2[i] = rnd;
}
for (i = 0; i < TextSize; i++) {
output += String.fromCharCode(Temp[i], Temp2[i]);
}
return output;
}
function unEncrypt(theText) {
output = new String;
Temp = new Array();
Temp2 = new Array();
TextSize = theText.length;
for (i = 0; i < TextSize; i++) {
Temp[i] = theText.charCodeAt(i);
Temp2[i] = theText.charCodeAt(i + 1);
}
for (i = 0; i < TextSize; i = i+2) {
output += String.fromCharCode(Temp[i] - Temp2[i]);
}
return output;
}
// End -->
</script>
第二步：把如下代码加入到<body>区域中
<center>
<form name=encform onsubmit="return false;">
<textarea name=box1 rows=5 cols=50>Typhoon Start JavaScript Fairyland</textarea>
<p>
<input type=button value="加密到下面文本框" onClick="this.form.box2.value=Encrypt(this.form.box1.value);">
<p>
<textarea name=box2 rows=5 cols=50></textarea>
<p>
<input type=button value="解密到下面文本框" onClick="this.form.box3.value=unEncrypt(this.form.box2.value);">
<p>
<textarea name=box3 rows=5 cols=50></textarea>
</form>
</center>