js写距离生日还有多少天

定义全局变量

var birthday ="2000-10-01";

daysTotal = 0;var year = date.getFullYear();//当前年份var _month = date.getMonth() + 1;//当前月份var _day =date.getDate();//当前天数var month = parseInt(<span style="font-size: 13.3333px;">birthday</span>.split('-')[1]);//生日月份var day = parseInt(<span style="font-size: 13.3333px;">birthday</span>.split('-')[2]);//生日天数if (month > _month){for (var j = _month; j < month; j++){daysTotal = TotalDays(year, j, daysTotal);}daysTotal = daysTotal + day - _day;} else if (month < _month) {for (var k = month; k < _month; k++) {daysTotal = TotalDays(year,k, daysTotal);}var dayFull = TotalDays(year, 0, daysTotal);daysTotal = dayFull - daysTotal + day - _day;} else{if (day >= _day) {daysTotal = day - _day;} else{daysTotal = TotalDays(year, 0, daysTotal) - (_day - day);}}

//JS判断闰年代码function isLeapYear(Year) {if (((Year % 4) == 0) && ((Year % 100) != 0) || ((Year % 400) == 0)) {return (true);} else { return (false); }}function TotalDays(year,month,days){switch (month) {case 1:case 3:case 5:case 7:case 8:case 10:case 12:days += 31;break;case 4:case 6:case 9:case 11:days += 30;break;case 2:if (isLeapYear(year)) {days += 29;} else {days += 28;}break;default:if (isLeapYear(year)) {days = 366;} else {days = 365;}break;}return days;}