PHP精确到毫秒秒杀倒计时实例

// 注意：php的时间是以秒算。js的时间以毫秒算
// 设置时区
date_default_timezone_set('PRC');
//配置每天的活动时间段
$starttimestr = date('Y-m-d H:i:s', strtotime(date('Y-m-d')));
$endtimestr = date('Y-m-d H:i:s', strtotime(date('Y-m-d', strtotime('+1 day'))));
$starttime = strtotime($starttimestr);
$endtime = strtotime($endtimestr);
$nowtime = time();
if ($nowtime < $starttime) {
exit("活动还没开始,活动时间是：{$starttimestr}至{$endtimestr}");
}
if ($endtime >= $nowtime) {
$lefttime = $endtime - $nowtime; //实际剩下的时间（秒）
} else {
$lefttime = 0;
exit("活动已经结束！");
}

var runtimes = 0;
function GetRTime() {
var lefttime = < ?php echo $lefttime; ? > * 1000 - runtimes * 1000;
if (lefttime >= 0) {
var nD = Math.floor(lefttime / (1000 * 60 * 60 * 24)) % 24;
var nH = Math.floor(lefttime / (1000 * 60 * 60)) % 24;
var nM = Math.floor(lefttime / (1000 * 60)) % 60;
var nS = Math.floor(lefttime / 1000) % 60;
document.getElementById("RemainD").innerHTML = nD;
document.getElementById("RemainH").innerHTML = nH;
document.getElementById("RemainM").innerHTML = nM;
document.getElementById("RemainS").innerHTML = nS;
if (lefttime == 5 * 60 * 1000) {
alert("还有最后五分钟！");
}
runtimes++;
setTimeout("GetRTime()", 1000);
} else {
alert('活动结束了！');
location.reload();
}
}
var Num = 0;
onload = function() {
Refresh();
setInterval("Refresh();", 100);
GetRTime();
}
function Refresh() {
if (Num < 10) {
document.getElementById("RemainL").innerHTML = Num;
Num = Num + 1;
} else {
Num = 0;
}
}