閏年功能不起作用

Question

如果在我的函數Kalender()中有一個閏年，但由於某些原因它會在閏年的二月份（例如2012）崩潰。與調試我沒有得到任何錯誤。由於某些原因，它不會將monthLength [1]更改爲28？

var dayNames = ['Zon', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat']; 
    //Volledige Dagnamen// 
    var dayNamesFull = ['Zondag', 'Maandag', 'Dinsdag', 'Woensdag', 'Donderdag', 'Vrijdag', 'Zaterdag']; 
    //Volledige Maandnamen// 
    var monthNames = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'Oktober', 'November', 'December']; 
    //Maand lengte van 0 - 11// 
    var monthLength = [31,28,31,30,31,30,31,31,30,31,30,31]; 
    //Nieuwe datum// 
    var today = new Date(); 
    //Vandaag// 
    var day = today.getDay(); 
    var currentDay = day; 
    //vandaag zoekmaand// 
    var month = today.getMonth(); 
    var currentMonth= month; 
    //vandaag// 
    var vandaag = today.getDate(); 

    //volledig jaar// 
    var Leapyear = today.getYear(); 
    var year = today.getFullYear(); 
    var currentYear = year; 

    //events in een array// 
    var act = ['Opa en Oma 50 jaar getrouwd','Afspraak met de baas', 'Lunchen met Oma','Kleding kopen met mijn moeder','Frank gaat verhuizen', 'School opdracht inleveren','Feestje van Henk', 'Kijken voor een nieuwe auto','Kinderen van school halen','Afspraak doktor 15.00','Zalf halen voor mijn voeten','Onderhoudsbeurt auto','Hond uitlaten','Vaccin krijgen voor reis naar jakarta','Vliegticket boeken', 'Kamer opruimen', 'Hond wegbrengen voor vlooienbehandeling', 'Ov-chipkaart opladen met geld', 'APK keuring Auto', 'Nieuwe velgen voor de auto ophalen in Loenen ad Vecht','Paardenstal opruimen','Golfen met mijn vrienden','Uit eten met mijn schoonfamilie','Werkoverleg overname', ' Bedrijfsbeleid aanpassen']; 

//Kalender schrijf functie//  
function Kalender() { 
    var buttons = '<button id="vorige" onclick="vorige()">Vorige</button><button id="volgende" onclick="volgende()">Volgende</button>' 
    var kalender = ""; 
//Leap Year// 
    if (month == 1){ 
     if (year % 4 == 0){ 
      monthLength = 29; 
     } 

    } 

document.getElementById('Header').innerHTML = monthNames[month]+" "+year+buttons; 
    kalender += '<table id="cal"><div id="taken"></div><div id="events"></div>'; 


     for (var j = 1; j <= monthLength[month]; j++) { 
      if ((vandaag == j) && (currentMonth == month) && (currentYear == year)) { 
        kalender += "<td class='tabeldagen' id='dagVandaag'><a id='dag"+j+"' onclick='addEvent (this.id)'>" + j; 
      } 
       else { 
        kalender += "<td id='"+j+"' class='tabeldagen'><a id='dag"+j+"' onclick='addEvent (this.id)'>"+j; 
       } 

        if (j % 7 == 0) { 

       kalender += "<tr>"; 
      } 
      kalender += '</td></a>'; 
     } 

    kalender += '</table>'; 
    document.getElementById('kalen').innerHTML = kalender; 
     document.getElementById('taken').innerHTML = dayNamesFull[currentDay]+" "+vandaag+" "+monthNames[currentMonth]; 

    } 

//Volgende Maand functie// 
function volgende() { 
month = month + 1; 
    if(month > 11) { 
     month = -1; 
     month = month + 1; 
     year = year + 1; 
    } 
     Kalender(); 
} 
//Vorige maand functie// 
function vorige() { 
    month = month - 1; 
    if(month < 0) { 
     month = + 12 ; 
     month = month - 1; 
     year = year - 1; 
    } 
     Kalender(); 
} 
//Voegt event toe aan De desbetreffende dag// 
function addEvent (id) { 
    if ((year == 2014) && (month == 10)) { 
     switch (id) { 
      case "dag1": 
       document.getElementById("events").innerHTML = act[1]; 
       break; 
      case "dag2": 
       document.getElementById("events").innerHTML = act[2]; 
       break; 
      case "dag3": 
       document.getElementById("events").innerHTML = act[0]; 
       break; 
      case "dag4": 
       document.getElementById("events").innerHTML = act[3]; 
       break; 
      case "dag5": 
       document.getElementById("events").innerHTML = act[4]; 
       break; 
      case "dag6": 
       document.getElementById("events").innerHTML = act[5]; 
       break; 
      case "dag7": 
       document.getElementById("events").innerHTML = act[6]; 
       break; 
      case "dag8": 
       document.getElementById("events").innerHTML = act[7]; 
       break; 
      case "dag9": 
       document.getElementById("events").innerHTML = act[8]; 
       break; 
      case "dag10": 
       document.getElementById("events").innerHTML = act[9]; 
       break; 
      case "dag11": 
       document.getElementById("events").innerHTML = act[10]; 
       break; 
      case "dag12": 
       document.getElementById("events").innerHTML = act[11]; 
       break; 
      case "dag13": 
       document.getElementById("events").innerHTML = act[12]; 
       break; 
      case "dag14": 
       document.getElementById("events").innerHTML = act[13]; 
       break; 
      case "dag15": 
       document.getElementById("events").innerHTML = act[14]; 
       break; 
      case "dag16": 
       document.getElementById("events").innerHTML = act[15]; 
       break; 
      case "dag17": 
       document.getElementById("events").innerHTML = act[16]; 
       break; 
      case "dag18": 
       document.getElementById("events").innerHTML = act[17]; 
       break; 
      case "dag19": 
       document.getElementById("events").innerHTML = act[18]; 
       break; 
      case "dag20": 
       document.getElementById("events").innerHTML = act[19]; 
       break; 
      case "dag21": 
       document.getElementById("events").innerHTML = act[20]; 
       break; 
      case "dag22": 
       document.getElementById("events").innerHTML = act[21]; 
       break; 
      case "dag23": 
       document.getElementById("events").innerHTML = act[22]; 
       break; 
      case "dag24": 
       document.getElementById("events").innerHTML = act[23]; 
       break; 
      case "dag25": 
       document.getElementById("events").innerHTML = act[24]; 
       break; 
      case "dag26": 
       document.getElementById("events").innerHTML = act[2]; 
       break; 
      case "dag27": 
       document.getElementById("events").innerHTML = act[6]; 
       break; 
      case "dag28": 
       document.getElementById("events").innerHTML = act[9]; 
       break; 
      case "dag29": 
       document.getElementById("events").innerHTML = act[12]; 
       break; 
      case "dag30": 
       document.getElementById("events").innerHTML = act[11]; 
       break; 
      case "dag31": 
       document.getElementById("events").innerHTML = act[0]; 
       break; 
     } 
    } 
} 

http://jsfiddle.net/nshd0o47/1/

Answer 1

你leapYear測試是不正確，這

if (year % 4 == 0) { 

應該像

if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) { 

維基百科給出了Leap year algorithm作爲

if (year is not divisible by 4) then (it is a common year) 
else 
if (year is not divisible by 100) then (it is a leap year) 
else 
if (year is not divisible by 400) then (it is a common year) 
else (it is a leap year) 

編輯

對不起，Kalendar也monthLength是一個數組 -

//Leap Year// 
if (month == 1){ 
    monthLength[1] = 28; 
    if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) { 
     monthLength[1] = 29; 
    } 
}