PHP 活动倒计时代码

<?php
header("content-type:text/html;charset=utf8");
date_default_timezone_set('PRC');
$tiem = "1531584000";

$strt = $tiem-time();
echo '截止时间：'.date('Y-m-d H:i:s',$tiem).'<p>';
echo '当前时间：'.date('Y-m-d H:i:s',time()).'<p>';
echo '倒计时：'.$strt.'<p>';

?>
<div class="time">
<span id="t_d">00天</span>
<span id="t_h">00时</span>
<span id="t_m">00分</span>
<span id="t_s">00秒</span>
</div>
<script>
function GetRTime(){
var EndTime= new Date('<?php echo date('Y-m-d H:i:s',$tiem) ?>');
var NowTime = new Date();
var t =EndTime.getTime() - NowTime.getTime();

var d=0;
var h=0;
var m=0;
var s=0;
if(t>=0){
d=Math.floor(t/1000/60/60/24);
h=Math.floor(t/1000/60/60%24);
m=Math.floor(t/1000/60%60);
s=Math.floor(t/1000%60);
}
document.getElementById("t_d").innerHTML = d + "天";
document.getElementById("t_h").innerHTML = h + "时";
document.getElementById("t_m").innerHTML = m + "分";
document.getElementById("t_s").innerHTML = s + "秒";
}
setInterval(GetRTime,0);

</script>