function isdate(intYear,intMonth,intDay){ 

  if(isNaN(intYear)||isNaN(intMonth)||isNaN(intDay)) return false;     

  if(intMonth>12||intMonth<1) return false;  

  if ( intDay<1||intDay>31)return false;  

  if((intMonth==4||intMonth==6||intMonth==9||intMonth==11)&&(intDay>30)) return false;  

  if(intMonth==2){  

     if(intDay>29) return false;    

     if((((intYear%100==0)&&(intYear%400!=0))||(intYear%4!=0))&&(intDay>28))return false;  

    }
  
  return true;  
}