效果:

<div class="nowTime">
<span></span>年
<span></span>月
<span></span>日
<span></span>:
<span></span>:
<span></span>
</div>
<script>
$(document).ready(function() {
function time() {
var date = new Date();
var n = date.getFullYear();
var y = date.getMonth() + 1;
var t = date.getDate();
var h = (date.getHours()<10)?"0"+date.getHours():date.getHours();
var m = (date.getMinutes()<10)?"0"+date.getMinutes():date.getMinutes();
var s = (date.getSeconds()<10)?"0"+date.getSeconds():date.getSeconds();
$(\'.nowTime span\').eq(0).html(n);
$(\'.nowTime span\').eq(1).html(y);
$(\'.nowTime span\').eq(2).html(t);
$(\'.nowTime span\').eq(3).html(h);
$(\'.nowTime span\').eq(4).html(m);
$(\'.nowTime span\').eq(5).html(s);
for (var i = 0; i < $(\'div\').length; i++) {
if ($(\'div\').eq(i).text().length == 1) {
$(\'div\').eq(i).html(function(index, html) {
return 0 + html;
});
}
}
}
time();
setInterval(time, 1000);
});
<script>