last-day-of-current-month.js

var getLastDayOfMonth = function(){
    var date = new Date();
    var lastDay = new Array([]);
    lastDay[0] = "31 januari";
    lastDay[1] = "28 februari";
    lastDay[2] = "31 maart";
    lastDay[3] = "30 april";
    lastDay[4] = "31 mei";
    lastDay[5] = "30 juni";
    lastDay[6] = "31 juli";
    lastDay[7] = "31 augustus";
    lastDay[8] = "30 september";
    lastDay[9] = "31 oktober";
    lastDay[10] = "30 november";
    lastDay[11] = "31 december";
    
    // Check voor schrikkeljaar
    if(date.getFullYear() % 4 === 0){
        lastDay[1] = "29 februari";
    }
    
    var lastDayThisMonth = lastDay[date.getMonth()];
    return lastDayThisMonth;
}

var addLastDayOfMonth = function(){
    var dateToAdd = getLastDayOfMonth();
    var positionToAddDate = document.getElementById('copy3').childNodes[0];
    
    positionToAddDate.appendChild( document.createTextNode(dateToAdd) );
}

addLastDayOfMonth();

var setCountdownDate = function(){
    var date = new Date();

    var lastDay = new Date(date.getYear(), date.getMonth() + 1, 0).getDate();
    var currentDay = date.getDate();
    var daysUntilEndOfMonth = lastDay - currentDay;

    var pancakeText = '';
    
    if(daysUntilEndOfMonth === 0){
        pancakeText = 'Laatste dag';
    }else if(daysUntilEndOfMonth === 1){
        pancakeText = 'Nog ' + daysUntilEndOfMonth + ' dag';
    }else if(daysUntilEndOfMonth <= 5){
        pancakeText = 'Nog ' + daysUntilEndOfMonth + ' dagen';
    }
    
    console.log(pancakeText);
    //return pancakeText;
};

setCountdownDate();