function b1(){
var year=(提取值)，month=(提取值)，day=(提取值)，sum=0;
for(var i = 1; i < month ; i++){
switch(i){
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:
sum += 31;
break;
case 2:
if(year%4==0 && year%100!=0 || year%400==0){
sum += 29;
}else{
sum += 28;
}
break;
default:sum += 30；
}
}console.log(year+"年"+month+"月"+day+"日是该年的第"+(sum+day)+"天");
}
