Ovulation Calculator
Estimated Ovulation Date: ${ovulationDay.toLocaleDateString(undefined, options)}
Fertile Window: ${fertileStart.toLocaleDateString(undefined, options)} - ${fertileEnd.toLocaleDateString(undefined, options)}
`; resultDiv.classList.remove('opacity-0','scale-95'); resultDiv.classList.add('opacity-100','scale-100'); currentMonth = ovulationDay.getMonth(); currentYear = ovulationDay.getFullYear(); buildCalendar(currentMonth, currentYear); calendarDiv.classList.remove('hidden'); }); prevMonthBtn.addEventListener('click', () => { currentMonth--; if (currentMonth < 0) { currentMonth = 11; currentYear--; } buildCalendar(currentMonth, currentYear); }); nextMonthBtn.addEventListener('click', () => { currentMonth++; if (currentMonth > 11) { currentMonth = 0; currentYear++; } buildCalendar(currentMonth, currentYear); }); function buildCalendar(month, year) { calendarGrid.innerHTML = ''; const monthStart = new Date(year, month, 1); const monthEnd = new Date(year, month + 1, 0); const startDay = monthStart.getDay(); const totalDays = monthEnd.getDate(); calendarTitle.textContent = monthStart.toLocaleString('default', { month: 'long', year: 'numeric' }); // Empty spaces for previous month for (let i = 0; i < startDay; i++) { const emptyCell = document.createElement('div'); calendarGrid.appendChild(emptyCell); } for (let day = 1; day <= totalDays; day++) { const date = new Date(year, month, day); const dayDiv = document.createElement('div'); dayDiv.classList.add('calendar-day'); if (date >= fertileStart && date <= fertileEnd) dayDiv.classList.add('fertile-day'); if (date.toDateString() === ovulationDay.toDateString()) dayDiv.classList.add('ovulation-day'); dayDiv.textContent = day; calendarGrid.appendChild(dayDiv); } }