js 获取当前月份 第一天和最后一天

var now = new Date(); //当前日期
var nowMonth = now.getMonth(); //当前月
var nowYear = now.getFullYear(); //当前年
//本月的开始时间
var monthStartDate = new Date(nowYear, nowMonth, 1);
//本月的结束时间
var monthEndDate = new Date(nowYear, nowMonth+1, 0);
var timeStar=Date.parse(monthStartDate)/1000;//s
var timeEnd=Date.parse(monthEndDate)/1000;//s