function filllfield31_keyword(){ 
 // this function is used to fill the lfield31_keyword list on load
}

function SelectSubCat(){
// ON selection of lfield31_keyword this function will work

removeAllOptions(document.drop_list.SubCat);
addOption(document.drop_list.SubCat, "", "Select Model - Optional", "");

if(document.drop_list.lfield31_keyword.value == 'Aeronca'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'American'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Husky'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Beechcraft'){
addOption(document.drop_list.SubCat,"Baron", "Baron");
addOption(document.drop_list.SubCat,"Bonanza", "Bonanza");
addOption(document.drop_list.SubCat,"Duchess", "Duchess");
addOption(document.drop_list.SubCat,"King", "King Air");
addOption(document.drop_list.SubCat,"Muskateer", "Muskateer");
addOption(document.drop_list.SubCat,"Skipper", "Skipper");
addOption(document.drop_list.SubCat,"Sierra", "Sierra");
addOption(document.drop_list.SubCat,"Sport", "Sport");
addOption(document.drop_list.SubCat,"Sundowner", "Sundowner");
addOption(document.drop_list.SubCat,"Twin Bonanza", "Twin Bonanza");
addOption(document.drop_list.SubCat,"", "All Beechcraft Models");
}
if(document.drop_list.lfield31_keyword.value == 'Bell_Helicopter'){
addOption(document.drop_list.SubCat,"206", "206");
addOption(document.drop_list.SubCat,"212", "212");
addOption(document.drop_list.SubCat,"412", "412");
addOption(document.drop_list.SubCat,"", "All Bell Models");
}
if(document.drop_list.lfield31_keyword.value == 'Breezer'){
addOption(document.drop_list.SubCat,"", "All Models");

}
if(document.drop_list.lfield31_keyword.value == 'Bellanca'){
addOption(document.drop_list.SubCat,"", "All Bellanca Models");
}
if(document.drop_list.lfield31_keyword.value == 'Cessna'){
addOption(document.drop_list.SubCat,"120", "120/140");
addOption(document.drop_list.SubCat,"150", "150");
addOption(document.drop_list.SubCat,"152", "152");
addOption(document.drop_list.SubCat,"170", "170");
addOption(document.drop_list.SubCat,"172", "172");
addOption(document.drop_list.SubCat,"177", "177");
addOption(document.drop_list.SubCat,"180", "180");
addOption(document.drop_list.SubCat,"182", "182");
addOption(document.drop_list.SubCat,"185", "185");
addOption(document.drop_list.SubCat,"195", "195");
addOption(document.drop_list.SubCat,"206", "206");
addOption(document.drop_list.SubCat,"210", "210");
addOption(document.drop_list.SubCat,"310", "310");
addOption(document.drop_list.SubCat,"340", "340");
addOption(document.drop_list.SubCat,"402", "402");
addOption(document.drop_list.SubCat,"421", "421");
addOption(document.drop_list.SubCat,"", "All Cessna Models");

}
if(document.drop_list.lfield31_keyword.value == 'Cirrus'){
addOption(document.drop_list.SubCat,"SR-20", "SR-20");
addOption(document.drop_list.SubCat,"SR-22", "SR-22");
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Columbia'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Commander'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Dassault'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'DeHavilland'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Diamond'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Dova'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Eurocopter'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Fairchild'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'FlyItalia'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Hughes'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Lancair'){
addOption(document.drop_list.SubCat,"", "All Lancair Models");
}

if(document.drop_list.lfield31_keyword.value == 'LearJet'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Luscombe'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Maule'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Mooney'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Navion'){
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Piper'){
addOption(document.drop_list.SubCat,"Archer", "Archer PA28-181");
addOption(document.drop_list.SubCat,"Aztec", "Aztec");
addOption(document.drop_list.SubCat,"Arrow", "Arrow PA28R");
addOption(document.drop_list.SubCat,"140", "Cherokee 140");
addOption(document.drop_list.SubCat,"160", "Cherokee 160");
addOption(document.drop_list.SubCat,"180", "Cherokee 180");
addOption(document.drop_list.SubCat,"6", "Cherokee 6");
addOption(document.drop_list.SubCat,"Piper_Comanche", "Comanche");
addOption(document.drop_list.SubCat,"Piper_Cub", "Cub");
addOption(document.drop_list.SubCat,"Dakota", "Dakota");
addOption(document.drop_list.SubCat,"Pilatus", "Pilatus");
addOption(document.drop_list.SubCat,"Saratoga", "Saratoga");
addOption(document.drop_list.SubCat,"Seminole", "Seminole");
addOption(document.drop_list.SubCat,"Seneca", "Seneca");
addOption(document.drop_list.SubCat,"Super", "Super Cub");
addOption(document.drop_list.SubCat,"Tomahawk", "Tomahawk");
addOption(document.drop_list.SubCat,"Twin_Comanche", "Twin Comanche");
addOption(document.drop_list.SubCat,"Warrior", "Warrior");
addOption(document.drop_list.SubCat,"", "All");
}
if(document.drop_list.lfield31_keyword.value == 'Pitts'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Robinson'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Schweizer'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Sikorsky'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Sting'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Socata'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Stinson'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Symphony'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Tecnam'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Waco'){
addOption(document.drop_list.SubCat,"", "All Models");
}
if(document.drop_list.lfield31_keyword.value == 'Zenith'){
addOption(document.drop_list.SubCat,"", "All Zenith Models");
}
if(document.drop_list.lfield31_keyword.value == 'Zlin'){
addOption(document.drop_list.SubCat,"", "All Models");
}


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

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);
}