<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<script type="text/javascript">
function getCookie(c_name) {
if (document.cookie.length > 0) {
c_start = document.cookie.indexOf(c_name + "=")
if (c_start != -1) {
c_start = c_start + c_name.length + 1
c_end = document.cookie.indexOf(";", c_start)
if (c_end == -1) c_end = document.cookie.length
return unescape(document.cookie.substring(c_start, c_end))
}
}
return ""
}
function setCookie(c_name, value, expiredays) {
var exdate = new Date()
exdate.setDate(exdate.getDate() + expiredays)
document.cookie = c_name + "=" + escape(value) +
((expiredays == null) ? "" : "; expires=" + exdate.toGMTString())
}
function checkCookie() {
username = getCookie(‘username‘)
if (username != null && username != "")
{ alert(‘Welcome again ‘ + username + ‘!‘) }
else {
username = prompt(‘Please enter your name:‘, "")
if (username != null && username != "") {
setCookie(‘username‘, username, 365)
}
}
}
</script>
</head>
<body onload="checkCookie()">
</body>
</html>
原文：http://www.cnblogs.com/fgb-com/p/4275365.html