function fillCategory(){ 
 // this function is used to fill the category list on load
addOption(document.reservation.Category, "Passenger", "Passenger Cars", "");
addOption(document.reservation.Category, "SUV", "Sport Utility Vehicles", "");
addOption(document.reservation.Category, "Vans", "Vans", "");
addOption(document.reservation.Category, "Pickups", "Pickups", "");
addOption(document.reservation.Category, "Trucks", "Trucks", "");
addOption(document.reservation.Category, "Trailers", "Trailers", "");
}

function SelectSubCat(){
// ON selection of category this function will work

removeAllOptions(document.reservation.SubCat);

addOption(document.reservation.SubCat, "", "Models", "");


if(document.reservation.Category.value == 'Passenger')
{
addOption(document.reservation.SubCat,"Mid Size", "Mid Size (Corolla)");
addOption(document.reservation.SubCat,"Full Size", "Full Size (Camry)");
}

if(document.reservation.Category.value == 'SUV')
{
addOption(document.reservation.SubCat,"Explorer", "Explorer (5 passengers)");
addOption(document.reservation.SubCat,"Expedition", "Expedition (7 -8 passengers)");
addOption(document.reservation.SubCat,"Suburban", "Suburban (7 -8 passengers)");
}

if(document.reservation.Category.value == 'Vans')
{
addOption(document.reservation.SubCat,"Mini Vans", "Mini Van (7 - 8 passengers)");
addOption(document.reservation.SubCat,"12 passenger Van", "12 Passenger Van");
addOption(document.reservation.SubCat,"15 passenger Van", "15 Passenger Van");
addOption(document.reservation.SubCat,"1/2 Ton Cargo Van", "1/2 Ton Cargo Van");
addOption(document.reservation.SubCat,"Extended Cargo Van", "Extended Cargo Van");
addOption(document.reservation.SubCat,"Handicap Lift Van", "Handicap Lift Van");
}

if(document.reservation.Category.value == 'Pickups')
{
addOption(document.reservation.SubCat,"1/2 Ton Pickup", "1/2 Ton Pickup");
addOption(document.reservation.SubCat,"3/4 Ton Pickup", "3/4 Ton Pickup");
addOption(document.reservation.SubCat,"1/2 Ton SuperCab Pickup", "1/2 Ton SuperCab Pickup");
addOption(document.reservation.SubCat,"3/4 Ton SuperCab Pickup", "3/4 Ton SuperCab Pickup");
addOption(document.reservation.SubCat,"3/4 Ton SuperCab Pickup (Diesel)", "3/4 Ton SuperCab Pickup (Diesel)");
addOption(document.reservation.SubCat,"1 Ton Crew Cab (Diesel)", "1 Ton Crew Cab (Diesel)");
addOption(document.reservation.SubCat,"1/2 Ton Ext. Cab Pickup (4x4)", "1/2 Ton Ext. Cab Pickup (4x4)");
}

if(document.reservation.Category.value == 'Trucks')
{
addOption(document.reservation.SubCat,"12 ft Stake Bed", "12 ft Stake Bed");
addOption(document.reservation.SubCat,"14 ft Stake Bed", "14 ft Stake Bed");
addOption(document.reservation.SubCat,"22 ft Stake Bed", "22 ft Stake Bed");
addOption(document.reservation.SubCat,"22 ft Flat Bed", "22 ft Flat Bed");
addOption(document.reservation.SubCat,"14 ft Box Van", "14 ft Box Van");
addOption(document.reservation.SubCat,"16 ft Box Van", "16 ft Box Van");
addOption(document.reservation.SubCat,"20 ft Box Van", "20 ft Box Van");
addOption(document.reservation.SubCat,"24 ft Box Van", "24 ft Box Van");
addOption(document.reservation.SubCat,"16 ft Refrigerated Truck", "16 ft Refrigerated Truck");
}

if(document.reservation.Category.value == 'Trailers')
{
addOption(document.reservation.SubCat,"12 ft Refrigerated Trailer", "12 ft Refrigerated Trailer");
addOption(document.reservation.SubCat,"10 - 12 ft Box Trailer", "10 - 12 ft Box Trailer");
}

}
////////////////// 

function removeAllOptions(selectbox)
{
	var i;
	for(i=selectbox.options.length-1;i>=0;i--)
	{
		//selectbox.options.remove(i);
		selectbox.remove(i);
	}
}


function addOption(selectbox, value, text )
{
	var optn = document.createElement("OPTION");
	optn.text = text;
	optn.value = value;

	selectbox.options.add(optn);
}