http://www.tocus.com.cn/?send=article_show&id=34&class=2
可以循环计时，而对于页面刷新，我们可以屏蔽鼠标右键、Ctrl+N、Shift+F10、Alt+F4、F11、F5刷新、退格键来达到效果
<script>
//屏蔽鼠标右键、Ctrl+N、Shift+F10、F11、F5刷新、退格键
function document.oncontextmenu(){event.returnValue=false}//屏蔽鼠标右键
function window.onhelp(){return false} //屏蔽F1帮助
function document.onkeydown(){
if((window.event.altKey)&&((window.event.keyCode==37)||(window.event.keyCode==39))){
//屏蔽Alt+方向键←
//屏蔽Alt+方向键→
event.returnValue=false
}
if((event.keyCode==8)||(event.keyCode==116)||(event.ctrlKey &&event.keyCode==82)){
//屏蔽退格删除键
//屏蔽F5刷新键
//Ctrl+R
event.keyCode=0
event.returnValue=false
}
if(event.keyCode==122){event.keyCode=0event.returnValue=false}//屏蔽F11
if(event.ctrlKey &&event.keyCode==78)event.returnValue=false //屏蔽Ctrl+n
if(event.shiftKey &&event.keyCode==121)event.returnValue=false //屏蔽shift+F10
if(window.event.srcElement.tagName=="A" &&window.event.shiftKey)
window.event.returnValue=false //屏蔽shift加鼠标左键新开一网页
if((window.event.altKey)&&(window.event.keyCode==115)){ //屏蔽Alt+F4
window.showModelessDialog("about:blank","","dialogWidth:1pxdialogheight:1px")
return false
}
}
</script>
<span id="span_dt_dt"></span><script language=javascript>
var daytemp=3//新增加变量
function show_date_time(){
window.setTimeout("show_date_time()", 1000)
BirthDay=new Date("02/26/2012")//改成你的计时日期
today=new Date()
timeold=(BirthDay.getTime()-today.getTime())
sectimeold=timeold/1000
secondsold=Math.floor(sectimeold)
msPerDay=24*60*60*1000
e_daysold=timeold/msPerDay
daysold=Math.floor(e_daysold)
e_hrsold=(e_daysold-daysold)*24
hrsold=Math.floor(e_hrsold)
if (hrsold <10){
hrsold = "0"+hrsold
}
e_minsold=(e_hrsold-hrsold)*60
minsold=Math.floor((e_hrsold-hrsold)*60)
if (minsold <10){
minsold = "0"+minsold
}
seconds=Math.floor((e_minsold-minsold)*60)
if (seconds <10){
seconds = "0"+seconds
}
//以下为增加代码：希望你测试通过，然后给分
if(daysold>=0)
{
document.getElementById("span_dt_dt").innerHTML=daysold+"<b>D</b>"+hrsold+"<b>H</b>"+minsold+"<b>M</b>"+seconds+"<b>S</b>"
}
else
{
if(daysold+daytemp>=0)
{
document.getElementById("span_dt_dt").innerHTML=(daysold+daytemp)+"<b>D</b>"+hrsold+"<b>H</b>"+minsold+"<b>M</b>"+seconds+"<b>S</b>"
}
else
{
daytemp=daytemp+3
}
}
}
show_date_time()
</script>
