JS获取及验证开始结束日期的方法

function validation(){var startdate=document.getElementById("start_tenancyDate_s").value;var enddate=document.getElementById("end_tenancyDate_s").value;var datesent=dateDiff(enddate,startdate);if(startdate==""){alert("请选择开始日期！");return false;}if(enddate==""){alert("请选择结束日期！");return false;}if(datesent>365){alert("选择的日期差超过最大值1年！");return false;}if(datesent<0){alert("选择的日期有误，结束日期必须大于开始日期！");return false;}else{return true;}}//调用该方法(主方法)function dateDiff(date1, date2){  var type1 = typeof date1, type2 = typeof date2;  if(type1 == 'string')  date1 = stringToTime(date1);  else if(date1.getTime)  date1 = date1.getTime();  if(type2 == 'string')  date2 = stringToTime(date2);  else if(date2.getTime)  date2 = date2.getTime();  return (date1 - date2) / (1000 * 60 * 60 * 24);//除1000是毫秒，不加是秒}//字符串转成Time(dateDiff)所需方法function stringToTime(string){  var f = string.split(' ', 2);  var d = (f[0] ? f[0] : '').split('-', 3);  var t = (f[1] ? f[1] : '').split(':', 3);  return (new Date(  parseInt(d[0], 10) || null,  (parseInt(d[1], 10) || 1)-1,  parseInt(d[2], 10) || null,  parseInt(t[0], 10) || null,  parseInt(t[1], 10) || null,  parseInt(t[2], 10) || null  )).getTime();}