有没有办法把这个已有的代码做成这样，而不是把结束日期作为一个预设值，让用户可以使用日期输入和时间输入选择一个结束日期。我有一种方法可以做到这一点，只使用HTML和Javascript与onClick()函数来避免使用PHP。任何帮助，我可以得到将是非常有用的。
<p id="demo"></p>
<script>
// Set the date we're counting down to
var countDownDate = new Date("Jan 5, 2021 15:37:25").getTime();
// Update the count down every 1 second
var x = setInterval(function() {
// Get today's date and time
var now = new Date().getTime();
// Find the distance between now and the count down date
var distance = countDownDate - now;
// Time calculations for days, hours, minutes and seconds
var days = Math.floor(distance / (1000 * 60 * 60 * 24));
var hours = Math.floor((distance % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));
var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
var seconds = Math.floor((distance % (1000 * 60)) / 1000);
// Output the result in an element with id="demo"
document.getElementById("demo").innerHTML = days + "d " + hours + "h "
+ minutes + "m " + seconds + "s ";
// If the count down is over, write some text
if (distance < 0) {
clearInterval(x);
document.getElementById("demo").innerHTML = "EXPIRED";
}
}, 1000);
</script>
<!DOCTYPE HTML>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
p {
text-align: center;
font-size: 60px;
margin-top: 0px;
}
</style>
</head>
<body>
<p id="demo"></p>
End Date <input type="datetime-local" id="endDate">
<button onclick="countdownTimeStart()">Start Timer</button>
<script>
// Set the date we're counting down to
function countdownTimeStart(){
var endDate = document.getElementById('endDate').value;
var dateObject = new Date(endDate);
var countDownDate = new Date(dateObject).getTime();
// Update the count down every 1 second
var x = setInterval(function() {
// Get today's date and time
var now = new Date().getTime();
// Find the distance between now and the count down date
var distance = countDownDate - now;
// Time calculations for days, hours, minutes and seconds
var days = Math.floor(distance / (1000 * 60 * 60 * 24));
var hours = Math.floor((distance % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));
var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
var seconds = Math.floor((distance % (1000 * 60)) / 1000);
// Output the result in an element with id="demo"
document.getElementById("demo").innerHTML = days + "d " + hours + "h "
+ minutes + "m " + seconds + "s ";
// If the count down is over, write some text
if (distance < 0) {
clearInterval(x);
document.getElementById("demo").innerHTML = "EXPIRED";
}
}, 1000);
}
</script>
</body>
</html>