<script type="text/javascript"> function show(){ var firstDay = new Date(); var year = firstDay.getFullYear(); var month = firstDay.getMonth() + 1; firstDay.setDate(1); //当月第一天 var lastDay = new Date(year, month, 0); //次月第一天的前一天 alert( year + "-" + month + "-" + firstDay.getDate() + "\n" + year + "-" + month + "-" + lastDay.getDate() ); } </script> <input type="button" onclick="show()" value="Show"/>