javascript中神奇的Date对象

// 获取月份天数
function getMonthDayCount(year, month) {
return new Date(year, month, 0).getDate();
}
console.log(getMonthDayCount(2017, 10)); // 31

function getAllMonthDayCount(year) {
var days = [31, new Date(year, 2, 0).getDate(), 31, 30, 31, 30, 31,文章来源地址28820.html 31, 30, 31, 30, 31];
return days;
}
console.log(getAllMonthDayCount(2016));// [31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

function isLeapYear(year) {
return (year % 4 == 0) && (year % 100 != 0 || year % 400 == 0);
}

function isLeapYear(year) {
return new Date(year, 2, 0).getDate() === 29;
}
console.log([
isLeapYear(2000),
isLeapYear(2016),
isLeapYear(2017),
isLeapYear(2018)
]); // [ true, true, false, false ]

// 10天后是几月几号
var dt = new Date('2016-12-25');
dt.setDate(dt.getDate() + 10);
console.lo文章来源地址28820.htmlg(dt.toLocaleDateString()); // 2017/1/4

// 10天前是几月www.yii666.com几号
var dt = new Date('2017-01-04');
dt.setDate(dt.getDate() - 10);
console.log(dt.toLocaleDateString()); // 2016/12/25