如何通过JavaScript获取一个月的最后一天？

<script language=javascript>
function leapYear(year)
{

if (year % 4 == 0) // basic rule

return true; // is leap year

/* else */ // else not needed when statement is "return"

return false; // is not leap year

}

function getDays(month, year)
{

// create array to hold number of days in each month

var ar = new Array(12);

ar[0] = 31; // January

ar[1] = (leapYear(year)) ? 29 : 28; // February

ar[2] = 31; // March

ar[3] = 30; // April

ar[4] = 31; // May

ar[5] = 30; // June

ar[6] = 31; // July

ar[7] = 31; // August

ar[8] = 30; // September

ar[9] = 31; // October

ar[10] = 30; // November

ar[11] = 31; // December

// return number of days in the specified month (parameter)

return ar[month];

}
alert(getDays(8-1,2006));

</script>