function fillCommand(){ 
 // this function is used to fill the category list on load
addOption(document.drop_list.command, "NCE", "NCE", "");
addOption(document.drop_list.command, "Digitrax", "Digitrax", "");
addOption(document.drop_list.command, "Lenz", "Lenz", "");
addOption(document.drop_list.command, "Hornby", "Hornby", "");
addOption(document.drop_list.command, "MRC", "MRC", "");
addOption(document.drop_list.command, "Roco", "Roco", "");
addOption(document.drop_list.command, "CVP", "CVP", "");
addOption(document.drop_list.command, "Analog(DC)", "Analog(DC)", "");
addOption(document.drop_list.command, "Other", "Other", "");
}

function fillCategory(){ 
 // this function is used to fill the category list on load
addOption(document.drop_list.Category, "HO-Scale", "HO-Scale", "");
addOption(document.drop_list.Category, "N-Scale", "N-Scale", "");
addOption(document.drop_list.Category, "Z-Scale", "Z-Scale", "");
}

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

removeAllOptions(document.drop_list.SubCat);
addOption(document.drop_list.SubCat, "", "Decoder", "");

if(document.drop_list.Category.value == 'HO-Scale'){
addOption(document.drop_list.SubCat,"221", "T1", "");
addOption(document.drop_list.SubCat,"236", "T4X", "");
addOption(document.drop_list.SubCat,"237", "T6X", "");
addOption(document.drop_list.SubCat,"231", "M1", "");
addOption(document.drop_list.SubCat,"233", "M3", "");
addOption(document.drop_list.SubCat,"234", "M4", "");
addOption(document.drop_list.SubCat,"244", "MC2", "");
addOption(document.drop_list.SubCat,"245", "MC4", "");
addOption(document.drop_list.SubCat,"246", "MC6", "");
addOption(document.drop_list.SubCat,"238", "A4X", "");
addOption(document.drop_list.SubCat,"239", "A6X", "");
addOption(document.drop_list.SubCat,"240", "FL2", "");
addOption(document.drop_list.SubCat,"240", "FL4", "");
addOption(document.drop_list.SubCat,"252", "DP2X", "");
addOption(document.drop_list.SubCat,"256", "DP2X-UK", "");


}

if(document.drop_list.Category.value == 'N-Scale'){
	document.getElementById("Harness").style.display = "none"; 
addOption(document.drop_list.SubCat,"279", "ASD4", "");
addOption(document.drop_list.SubCat,"242", "AMD4", "");
addOption(document.drop_list.SubCat,"295", "ALD4", "");
addOption(document.drop_list.SubCat,"253", "CN", "");
addOption(document.drop_list.SubCat,"254", "CN-GP", "");
addOption(document.drop_list.SubCat,"312", "EUN651", "");
addOption(document.drop_list.SubCat,"318", "IMD4", "");
addOption(document.drop_list.SubCat,"321", "IMF4", "");
addOption(document.drop_list.SubCat,"322", "IMFP4", "");
addOption(document.drop_list.SubCat,"323", "IMFTA4", "");
addOption(document.drop_list.SubCat,"324", "IMFTB4", "");
addOption(document.drop_list.SubCat,"328", "K0D8-A", "");
addOption(document.drop_list.SubCat,"333", "K0D8-B", "");
addOption(document.drop_list.SubCat,"334", "K0D8-C", "");
addOption(document.drop_list.SubCat,"335", "K0D8-D", "");
addOption(document.drop_list.SubCat,"296", "K1D4", "");
addOption(document.drop_list.SubCat,"313", "K1D4-NC", "");
addOption(document.drop_list.SubCat,"297", "K2D4", "");
addOption(document.drop_list.SubCat,"294", "K3D3", "");
addOption(document.drop_list.SubCat,"243", "MP15N", "");
addOption(document.drop_list.SubCat,"241", "VO-1000", "");

}

if(document.drop_list.Category.value == 'Z-Scale'){
addOption(document.drop_list.SubCat,"293", "Z2", "");
addOption(document.drop_list.SubCat,"336", "MZA4", "");
}

}

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

removeAllOptions(document.drop_list.Model);
addOption(document.drop_list.Model, "", "Model", "");

if(document.drop_list.command.value == 'NCE'){
addOption(document.drop_list.Model,"Power Cab", "Power Cab", "");
addOption(document.drop_list.Model,"Pro Cab", "Pro Cab", "");

}

if(document.drop_list.command.value == 'Lenz'){
addOption(document.drop_list.Model,"LV101", "LV101", "");
addOption(document.drop_list.Model,"LV102", "LV102", "");
addOption(document.drop_list.Model,"LV200", "LV200", "");

}

if(document.drop_list.command.value == 'Digitrax'){
addOption(document.drop_list.Model,"DCS50(Zephyr)", "DCS50(Zephyr)", "");
addOption(document.drop_list.Model,"DB150", "DB150", "");
addOption(document.drop_list.Model,"DCS100", "DCS100", "");
addOption(document.drop_list.Model,"DCS200", "DCS200", "");
}

if(document.drop_list.command.value == 'MRC'){
addOption(document.drop_list.Model,"Prodigy Express", "Prodigy Express", "");
addOption(document.drop_list.Model,"Prodigy Advance", "Prodigy Advance", "");
addOption(document.drop_list.Model,"Prodigy Wireless", "Prodigy Wireless", "");
}

if(document.drop_list.command.value == 'Hornby'){
addOption(document.drop_list.Model,"R8213(Select)", "R8213(Select)", "");
addOption(document.drop_list.Model,"R8214(Elite)", "R8213(Elite)", "");

}

if(document.drop_list.command.value == 'Roco'){
addOption(document.drop_list.Model,"Digital Locomouse 3", "Digital Locomouse 3", "");
addOption(document.drop_list.Model,"multiMAUS", "multiMAUS", "");
addOption(document.drop_list.Model,"multiMAUSpro", "multiMAUSpro", "");
}

if(document.drop_list.command.value == 'CVP'){
addOption(document.drop_list.Model,"Air Wire 900", "Air Wire 900", "");
addOption(document.drop_list.Model,"EasyDCC", "EasyDCC", "");
}

}

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

removeAllOptions(document.drop_list.Harness);
addOption(document.drop_list.Harness, "", "Harness", "");

if(document.drop_list.SubCat.value == '221'){
document.getElementById("Harness").style.display = "inline";  
addOption(document.drop_list.Harness,"SH", "SH", "");
addOption(document.drop_list.Harness,"MH", "MH", "");
addOption(document.drop_list.Harness,"LH", "LH", "");
addOption(document.drop_list.Harness,"UK", "UK", "");
addOption(document.drop_list.Harness,"1 in.", "1 in.", "");
addOption(document.drop_list.Harness,"C628", "C628", "");
addOption(document.drop_list.Harness,"E6", "E6", "");
addOption(document.drop_list.Harness,"E7", "E7", "");
addOption(document.drop_list.Harness,"PA", "PA", "");
addOption(document.drop_list.Harness,"P2K", "P2K", "");
addOption(document.drop_list.Harness,"UK-SH", "UK-SH", "");
addOption(document.drop_list.Harness,"UK-MH", "UK-MH", "");
addOption(document.drop_list.Harness,"UK-LH", "UK-LH", "");
addOption(document.drop_list.Harness,"VO", "VO", "");
}

if(document.drop_list.SubCat.value == '236'){
	document.getElementById("Harness").style.display = "inline";  
addOption(document.drop_list.Harness,"SH", "SH", "");
addOption(document.drop_list.Harness,"MH", "MH", "");
addOption(document.drop_list.Harness,"LH", "LH", "");
addOption(document.drop_list.Harness,"UK", "UK", "");
addOption(document.drop_list.Harness,"1 in.", "1 in.", "");
addOption(document.drop_list.Harness,"C628", "C628", "");
addOption(document.drop_list.Harness,"E6", "E6", "");
addOption(document.drop_list.Harness,"E7", "E7", "");
addOption(document.drop_list.Harness,"PA", "PA", "");
addOption(document.drop_list.Harness,"P2K", "P2K", "");
addOption(document.drop_list.Harness,"UK-SH", "UK-SH", "");
addOption(document.drop_list.Harness,"UK-MH", "UK-MH", "");
addOption(document.drop_list.Harness,"UK-LH", "UK-LH", "");
addOption(document.drop_list.Harness,"VO", "VO", "");
}

if(document.drop_list.SubCat.value == '237'){
	document.getElementById("Harness").style.display = "inline";  
addOption(document.drop_list.Harness,"SH", "SH", "");
addOption(document.drop_list.Harness,"MH", "MH", "");
addOption(document.drop_list.Harness,"LH", "LH", "");
addOption(document.drop_list.Harness,"UK", "UK", "");
addOption(document.drop_list.Harness,"1 in.", "1 in.", "");
addOption(document.drop_list.Harness,"C628", "C628", "");
addOption(document.drop_list.Harness,"E6", "E6", "");
addOption(document.drop_list.Harness,"E7", "E7", "");
addOption(document.drop_list.Harness,"PA", "PA", "");
addOption(document.drop_list.Harness,"P2K", "P2K", "");
addOption(document.drop_list.Harness,"UK-SH", "UK-SH", "");
addOption(document.drop_list.Harness,"UK-MH", "UK-MH", "");
addOption(document.drop_list.Harness,"UK-LH", "UK-LH", "");
addOption(document.drop_list.Harness,"VO", "VO", "");
}

if(document.drop_list.SubCat.value == '244'){
	document.getElementById("Harness").style.display = "inline";  
addOption(document.drop_list.Harness,"SH", "SH", "");
addOption(document.drop_list.Harness,"MH", "MH", "");
addOption(document.drop_list.Harness,"LH", "LH", "");
addOption(document.drop_list.Harness,"UK", "UK", "");
addOption(document.drop_list.Harness,"1 in.", "1 in.", "");
addOption(document.drop_list.Harness,"C628", "C628", "");
addOption(document.drop_list.Harness,"E6", "E6", "");
addOption(document.drop_list.Harness,"E7", "E7", "");
addOption(document.drop_list.Harness,"PA", "PA", "");
addOption(document.drop_list.Harness,"P2K", "P2K", "");
addOption(document.drop_list.Harness,"UK-SH", "UK-SH", "");
addOption(document.drop_list.Harness,"UK-MH", "UK-MH", "");
addOption(document.drop_list.Harness,"UK-LH", "UK-LH", "");
addOption(document.drop_list.Harness,"VO", "VO", "");
}

if(document.drop_list.SubCat.value == '245'){
	document.getElementById("Harness").style.display = "inline";  
addOption(document.drop_list.Harness,"SH", "SH", "");
addOption(document.drop_list.Harness,"MH", "MH", "");
addOption(document.drop_list.Harness,"LH", "LH", "");
addOption(document.drop_list.Harness,"UK", "UK", "");
addOption(document.drop_list.Harness,"1 in.", "1 in.", "");
addOption(document.drop_list.Harness,"C628", "C628", "");
addOption(document.drop_list.Harness,"E6", "E6", "");
addOption(document.drop_list.Harness,"E7", "E7", "");
addOption(document.drop_list.Harness,"PA", "PA", "");
addOption(document.drop_list.Harness,"P2K", "P2K", "");
addOption(document.drop_list.Harness,"UK-SH", "UK-SH", "");
addOption(document.drop_list.Harness,"UK-MH", "UK-MH", "");
addOption(document.drop_list.Harness,"UK-LH", "UK-LH", "");
addOption(document.drop_list.Harness,"VO", "VO", "");
}

if(document.drop_list.SubCat.value == '246'){
	document.getElementById("Harness").style.display = "inline";  
addOption(document.drop_list.Harness,"SH", "SH", "");
addOption(document.drop_list.Harness,"MH", "MH", "");
addOption(document.drop_list.Harness,"LH", "LH", "");
addOption(document.drop_list.Harness,"UK", "UK", "");
addOption(document.drop_list.Harness,"1 in.", "1 in.", "");
addOption(document.drop_list.Harness,"C628", "C628", "");
addOption(document.drop_list.Harness,"E6", "E6", "");
addOption(document.drop_list.Harness,"E7", "E7", "");
addOption(document.drop_list.Harness,"PA", "PA", "");
addOption(document.drop_list.Harness,"P2K", "P2K", "");
addOption(document.drop_list.Harness,"UK-SH", "UK-SH", "");
addOption(document.drop_list.Harness,"UK-MH", "UK-MH", "");
addOption(document.drop_list.Harness,"UK-LH", "UK-LH", "");
addOption(document.drop_list.Harness,"VO", "VO", "");
}

if(document.drop_list.SubCat.value == '231'){
	document.getElementById("Harness").style.display = "inline";  
addOption(document.drop_list.Harness,"SH", "SH", "");
addOption(document.drop_list.Harness,"MH", "MH", "");
addOption(document.drop_list.Harness,"LH", "LH", "");
addOption(document.drop_list.Harness,"UK", "UK", "");
}

if(document.drop_list.SubCat.value == '233'){
	document.getElementById("Harness").style.display = "inline";  
addOption(document.drop_list.Harness,"SH", "SH", "");
addOption(document.drop_list.Harness,"MH", "MH", "");
addOption(document.drop_list.Harness,"LH", "LH", "");
addOption(document.drop_list.Harness,"UK", "UK", "");
}

if(document.drop_list.SubCat.value == '234'){
	document.getElementById("Harness").style.display = "inline";  
addOption(document.drop_list.Harness,"SH", "SH", "");
addOption(document.drop_list.Harness,"MH", "MH", "");
addOption(document.drop_list.Harness,"LH", "LH", "");
addOption(document.drop_list.Harness,"UK", "UK", "");
}
addOption(document.drop_list.Harness, "", "None", "");


}


////////////////// 

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);
}