<script> function isLeap(){ var year =2004 ; var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)); if (isleap) alert(year+" is leap") ; else alert(year+" is not leap") ; } </script>
var isleap=(year%4==0&&(year%100!=0||year%400==0));
<script> function check(year){ alert(year+(new Date(year,2,0).getDate()==29?"是":"不是")+"闰年") } check(2000); check(1980); check(1900); </script>
function isLeap(){
var year =2004 ;
var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
if (isleap)
alert(year+" is leap") ;
else
alert(year+" is not leap") ;
}
</script>
function check(year){
alert(year+(new Date(year,2,0).getDate()==29?"是":"不是")+"闰年")
}
check(2000);
check(1980);
check(1900);
</script>