<script type="text/javascript"> function changedate() { // フォームと各年月日のname属性を指定 var formN = document.form1; var tYear = formN.year; var tMonth = formN.month; var tDays = formN.days; var selectY = tYear.options[tYear.selectedIndex].value; var selectM = tMonth.options[tMonth.selectedIndex].value; var selectD = tDays.options[tDays.selectedIndex].value; var dateObj = new Date(selectY, selectM, 0); tDay