有哪个大神会那个用JS写出判断出自己是一年当中的第几天的题目吗？

Answer 1

function getDaysInYear(y, m, d) {
    return (new Date(y, m - 1, d) - new Date(y, 0, 0)) / 86400000;
}

var result = getDaysInYear(2018, 1, 16);

console.log(result); // => 16

Answer 2

function fewDays(y,m,d) {

    var arr = [31,28,31,30,31,30,31,31,30,31,30,31];

    var day = 0;

    if(y%4 == 0){arr[1] = 29;}

    if(m > 12){m=12}

    if(d >arr[m-1]){d=arr[m-1]}

    

    for(let i = 0;i<m-1;i++){

            day += arr[i]; 

    }

    return day+d

}

console.log(fewDays(2000,4,8))

console.log(fewDays(2001,5,9))

console.log(fewDays(2002,6,10))

console.log(fewDays(2003,7,11))