JS判断结束时间不能小于开始时间并且间隔不能超过30天

<script language="javascript">
function CheckForm()
 {
  var jsrq=document.getElementById("sLtime").value; //结束
  var ksrq=document.getElementById("sRtime").value; //开始
  var now=""+new Date().getYear()+"-"+(new Date().getMonth()+1)+"-"+new Date().getDate()+"";
  var aDate = jsrq.split("-");
  var oDate1 = new Date(aDate[1] + '-' + aDate[2] + '-' + aDate[0]);  //结束日期
   aDate = ksrq.split("-");
   var oDate2 = new Date(aDate[1] + '-' + aDate[2] + '-' + aDate[0]);    //开始日期
   if(oDate1<=oDate2) {
          alert("结束日期必须大于开始日期!");
          return false;
       }
    else {
         var ts = dateDiff('D', ksrq, jsrq) ;
         //document.getElementById("iDays").value=ts
              if(ts>=30)
                      {
                      alert('时间段不能超过30天');
                      return false;
                      }
                }
 }
  function dateDiff(interval, date1, date2)
    {
        var objInterval = {'D' : 1000 * 60 * 60 * 24, 'H' : 1000 * 60 * 60,
                           'M' : 1000 * 60, 'S' : 1000, 'T' : 1};
        interval = interval.toUpperCase();
        var dt1 = Date.parse(date1.replace(/-/g, '/'));
        var dt2 = Date.parse(date2.replace(/-/g, '/'));
        try
        {
            return Math.round((dt2 - dt1) / eval('(objInterval.' + interval + ')'));
        }
        catch (e)
        {
            return e.message;
        }
    }
</script>