var dateDropdown = document.getElementById('dobYear'); var currentYear = new Date().getFullYear(); var earliestYear = 1900; while (currentYear >= earliestYear) { var age = new Date().getFullYear() - currentYear; var dateOption = document.createElement('option'); dateOption.text = currentYear; dateOption.value = currentYear; if (age < 18) { dateOption.hidden = true; } dateDropdown.add(dateOption); currentYear -= 1; }