Javascript中Cookie主要存储于客户端的计算机中，用于存放已访问的站点信息，Cookie最大约为4k.以下实例主要用于页面在刷新时保存数据，具体的用法如下所示：
<html>
<head><title></title>
</head>
<body>
<script type="text/javascript">
window.onload = function ()
{
PersentValue();
} function AddValueToCookie()
{
setCookie("ID", 100);
setCookie("Name", 'Tom');
PersentValue();
} function ClearValueOfCookie()
{
SetCookieToExpire("ID");
SetCookieToExpire("Name");
PersentValue();
} function PersentValue()
{
var id = getCookie("ID");
var name = getCookie("Name");
if (id == null) {
alert('Waiting for set value to ID');
}
else {
alert(id);
} if (name == null) {
alert('Waiting for set value to Name');
}
else {
alert(name);
}
} function setCookie(name, value) {
var Days = 30;
var exp = new Date();
exp.setTime(exp.getTime() + Days * 24 * 60 * 60 * 1000);
document.cookie = name + "=" + escape(value) + ";expires=" + exp.toGMTString();
} function getCookie(name) {
var arg = name + "=";
var alen = arg.length;
var clen = document.cookie.length;
var i = 0;
while (i < clen) {
var j = i + alen;
if (document.cookie.substring(i, j) == arg) {
return getCookieVal(j);
}
i = document.cookie.indexOf(" ", i) + 1;
if (i == 0) break;
}
return null;
} function getCookieVal(offset) {
var endstr = document.cookie.indexOf(";", offset);
if (endstr == -1) {
endstr = document.cookie.length;
}
return unescape(document.cookie.substring(offset, endstr));
} function SetCookieToExpire(name) {
var exp = new Date();
exp.setTime(exp.getTime() - 1);
var cval = getCookie(name);
if (cval != null) document.cookie = name + "=" + cval + ";expires=" + exp.toGMTString();
}
</script>
<input type="button" value="AddValue" onclick="AddValueToCookie();" />
<input type="button" value="ClearValue" onclick="ClearValueOfCookie();" />
</body>
</html>