应用javascript 去计算某月某日是今年的第几天?不考虑闰月!
var mouth=Number(prompt("请输入月份"));
var day=Number(prompt("请输入几号"));
var days=0;
switch (mouth-1){
case 11:days
+=30;
case 10:days
+=31;
case 9:days
+=30;
case 8:days
+=31;
case 7:days
+=31;
case 6:days
+=30;
case 5:days
+=31;
case 4:days
+=30;
case 3:days
+=31;
case 2:days
+=28;
case 1:days
+=31;}
days += day
;
alert("这个日子是今年的第"+days+"天");