Question

我正在做一个计划，在一年中的某一天，建立日期和月份。

我编写了这段代码，但当输入值> 31时，它无法正常工作。我希望有人会帮助我，谢谢你。

<script>


var dayn=[31,28,31,30,31,30,31,31,30,31,30,31];
var vettmonth=["January", "February", "March", "April", "May","June","July","August","September","October","November","Dicember"];

function f()
    {
    var nday, day, month, count=0;

    nday=eval(ngiorno.value);

    for(var i=0;i<12;i++){
       if (nday>dayn[i]){
          count=count+dayn[i]; }
       else if(nday<32){
          day=nday;
          month=vettmonth[i]; 
          break;
       } 
       else if(nday>31 && nday<dayn[i+1]+count){
          day=nday-count;
          month=vettmonth[i+1]; 
          break;
       } 
    }

    mmese.value=month;
    ggiorno.value=day;      

}
</script>

Answer 1

你已经让它变得更复杂了。你可以这样做：

＆＃13;

const vettmonth=["January", "February", "March", "April", "May","June","July","August","September","October","November","Dicember"];


let dayOfTheYear = 120;
let date = new Date(new Date().getFullYear(), 0, 1); // Start of this year
date.setDate(120); // increase the date by "dayOfTheYear"
console.log("Month:",vettmonth[date.getMonth()], "Day:", date.getDate());

＆＃13;

如果您不使用Date个对象，则可以这样做：

＆＃13;

const dayn = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
const vettmonth = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];

let dayOfTheYear = 120;
let monthIndex = 0;
let day = 0;

for(let i = 0, sum = 0; i < dayn.length; i++){
  sum+=dayn[i];
  if(dayOfTheYear <= sum){
    monthIndex = i;
    day = (sum - dayOfTheYear) + 1;
    break;
  }
}

console.log("Month:", vettmonth[monthIndex], "Day:", day);

＆＃13;

Answer 2

问题是，在经历这几个月之后，你永远不会减少nday。因此，如果nday > 31，nday > dayn[i]每次都为真，那么您永远不会执行设置else if和day的{{1}}块。您需要从month中减去dayn[i]。

不需要两个nday块。当else if阻止失败时，您将在正确的月份内完成。并且也不需要if变量。

＆＃13;

count

＆＃13;

使用javascript的日和年

2 个答案: