网页中实现一个计算当年还剩多少时间的倒数计时程序，要求网页上实时动态显示“××年还剩××天××时××分××秒”

<script type="text/javascript">

function counter() {

var date = new Date();

var year = date.getFullYear();

var date2 = new Date(year, 12, 31, 23, 59, 59);

var time = (date2 - date)/1000;

var day =Math.floor(time/(24*60*60))

var hour = Math.floor(time%(24*60*60)/(60*60))

var minute = Math.floor(time%(24*60*60)%(60*60)/60);

var second = Math.floor(time%(24*60*60)%(60*60)%60);

var str = year + "年还剩"+day+"天"+hour+"时"+minute+"分"+second+"秒";

document.getElementById("input").value = str;

}

window.setInterval("counter()", 1000);

</script>