js判斷時間大小

function validTime(startTime,endTime){
   var arr1 = startTime.split("-");
   var arr2 = endTime.split("-");
   var date1=new Date(parseInt(arr1[0]),parseInt(arr1[1])-1,parseInt(arr1[2]),0,0,0);
   var date2=new Date(parseInt(arr2[0]),parseInt(arr2[1])-1,parseInt(arr2[2]),0,0,0);
     if(date1.getTime()>date2.getTime()) {                               
               alert('結束日期不能小於開始日期',this);
               return false;
         }else{
         return true;
         }
         return false;
}