废话不多说，直接上代码！
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<p id="demo">单击按钮。</p>
<button onclick="getNowFormatDate()">我点点点</button>
<div id="da"></div>
<script>
function getNowFormatDate() {
var date = new Date();
var seperator1 = "-";
var seperator2 = ":";
var month = date.getMonth() + 1;
var strDate = date.getDate();
if (month >= 1 && month <= 9) {
month = "0" + month;
}
if (strDate >= 0 && strDate <= 9) {
strDate = "0" + strDate;
}
var currentdate = date.getFullYear() + seperator1 + month + seperator1 + strDate + " " + date.getHours() + seperator2 + date.getMinutes() + seperator2 + date.getSeconds();
var t = document.getElementById("da");
t.innerHTML = currentdate
console.log(currentdate);
}
</script>
</body>
</html>