function checkdata()

{

	 
	  if (document.car.car_type.value == 'Car Type') {

         alert ("The ['Car Type'] field requires an entry.");

         document.car.car_type.focus();

         return false;

     }

  
     
  if (document.car.pickup_day.value == 'Day' || document.car.pickup_month.value== 'Month' || document.car.pickup_year.value== 'Year' ) {

         alert ("The ['Pick Up Date'] field requires an entry.");

         document.car.pickup_day.focus();

         return false;

     }
	 
	 if (document.car.pickup_hour.value == 'Hour' || document.car.pickup_min.value == 'Min') {

         alert ("The ['Pick Up Time'] field requires an entry.");

         document.car.pickup_hour.focus();

         return false;

     }
	 
	 
	 if (document.car.pickup_city.value == 'Pick Up City') {

         alert ("The ['Pick Up City'] field requires an entry.");

         document.car.pickup_city.focus();

         return false;

     }
	 if (document.car.pickup_location.value == 'Location') {

         alert ("The ['Pick Up Location'] field requires an entry.");

         document.car.pickup_location.focus();

         return false;

     }
	   if (document.car.dropoff_day.value == 'Day' || document.car.dropoff_month.value == 'Month' || document.car.dropoff_year.value == 'Year' ) {

         alert ("The ['Drop off Date'] field requires an entry.");

         document.car.dropoff_day.focus();

         return false;

     }
	 
	 if (document.car.dropoff_hour.value == 'Hour' || document.car.dropoff_min.value == 'Min') {

         alert ("The ['Drop off Time'] field requires an entry.");

         document.car.dropoff_hour.focus();

         return false;

     }
	 
	 
	 if (document.car.dropoff_city.value == 'Dropoff City') {

         alert ("The ['Drop off City'] field requires an entry.");

         document.car.dropoff_city.focus();

         return false;

     }
	 if (document.car.dropoff_location.value == 'Location') {

         alert ("The ['Drop off Location'] field requires an entry.");

         document.car.dropoff_location.focus();

         return false;

     }
	  if (car.dropoff_year.value < car.pickup_year.value) {

         alert ("['Drop off'] year is smaller than ['Pick up'] year.");

         document.car.dropoff_year.focus();

         return false;
}
else{
	if(car.dropoff_month.value < car.pickup_month.value)
		if(car.dropoff_year.value == car.pickup_year.value){
	 alert ("['Drop off'] month is smaller than ['Pick up'] month.");
		document.car.dropoff_month.focus();

         return false;
		}

	if(car.dropoff_day.value < car.pickup_day.value)
		if(car.dropoff_month.value == car.pickup_month.value && car.dropoff_year.value == car.pickup_year.value){
	 alert ("['Drop off'] day is smaller than ['Pick up'] day.");
		document.car.dropoff_day.focus();

         return false;
	}
	
	}
	if(car.dropoff_day.value==car.pickup_day.value && car.dropoff_month.value==car.pickup_month.value && car.dropoff_year.value==car.pickup_year.value)
		if(car.dropoff_hour.value<car.pickup_hour.value){
		 alert ("['Drop off'] time is smaller than ['Pick up'] time.");
		document.car.dropoff_hour.focus();
			return false;
		}
     return true;



}