<!-- 把下列代码加到BODY中 -->
<body>
<script>
var cookieString = new String(document.cookie)
var cookieHeader = 'happy_pop' //更换happy_pop为任意名称
var beginPosition = cookieString.indexOf(cookieHeader)
if (beginPosition <0){
window.open('http://www.knowsky.com/index.html','','top=0,left=0,width=787,height=480,toolbar=yes,menubar=yes,scrollbars=yes,resizable=yes,location=yes,status=yes');
var Then = new Date()
Then .setTime(Then.getTime() + 12*60*60*1000 ) //同一ip设置过期时间，即多长间隔跳出一次
document.cookie = 'happy_pop=yes;expires='+ Then.toGMTString() //更换happy_pop和第4行一样的名称
}//more javascript from http://www.knowsky.com
</script>
</body>