关于JS取日期

1.获取当前月的第一天
var date=new Date();
date.setDate(1);
var year=date.getFullYear();
var month=date.getMonth()+1;
month=(month.toString().length=1)?"0"+month:month;
var day=date.getDate();
return year+"-"+month+"-"+day;
2.获取当前月的最后一天
var date = new Date(), y = date.getFullYear(), m = date.getMonth();
var lastDay = new Date(y, m + 1, 0);

var year=lastDay .getFullYear();
var month=lastDay .getMonth()+1;
month=(month.toString().length=1)?"0"+month:month;
var day=lastDay .getDate();
return year+"-"+month+"-"+day;