function fillorigin(){ 
 // this function is used to fill the origin list on load
addOption(document.drop_list.origin, "", "Any Irish Airport", "");
addOption(document.drop_list.origin, "DUB", "Dublin", "");
addOption(document.drop_list.origin, "ORK", "Cork", "");
addOption(document.drop_list.origin, "SNN", "Shannon", "");
addOption(document.drop_list.origin, "NOC", "Knock", "");
}

function SelectDest(){
// ON selection of origin this function will work

removeAllOptions(document.drop_list.Dest);
addOption(document.drop_list.Dest, "", "All Destinations", "");

if(document.drop_list.origin.value == ''){
addOption(document.drop_list.Dest,"FAO", "Algarve");
addOption(document.drop_list.Dest,"BUL", "Bulgaria");
addOption(document.drop_list.Dest,"AGP", "Costa del Sol");
addOption(document.drop_list.Dest,"LCA", "Cyprus");
addOption(document.drop_list.Dest,"FUE", "Fuerteventura");
addOption(document.drop_list.Dest,"LPA", "Gran Canaria");
addOption(document.drop_list.Dest,"ACE", "Lanzarote");
addOption(document.drop_list.Dest,"RVN", "Lapland");
addOption(document.drop_list.Dest,"LIS", "Lisbon");
addOption(document.drop_list.Dest,"FNC", "Maderia");
addOption(document.drop_list.Dest,"AGA", "Morocco");
addOption(document.drop_list.Dest,"NAP", "Sorrento");
addOption(document.drop_list.Dest,"CTA", "Sicily");
addOption(document.drop_list.Dest,"IZM", "Turkey");
addOption(document.drop_list.Dest,"MIR", "Tunisia");
}


if(document.drop_list.origin.value == 'DUB'){
addOption(document.drop_list.Dest,"FAO", "Algarve");
addOption(document.drop_list.Dest,"BUL", "Bulgaria");
addOption(document.drop_list.Dest,"AGP", "Costa del Sol");
addOption(document.drop_list.Dest,"LCA", "Cyprus");
addOption(document.drop_list.Dest,"FUE", "Fuerteventura");
addOption(document.drop_list.Dest,"LPA", "Gran Canaria");
addOption(document.drop_list.Dest,"ACE", "Lanzarote");
addOption(document.drop_list.Dest,"RVN", "Lapland");
addOption(document.drop_list.Dest,"LIS", "Lisbon");
addOption(document.drop_list.Dest,"FNC", "Maderia");
addOption(document.drop_list.Dest,"AGA", "Morocco");
addOption(document.drop_list.Dest,"NAP", "Sorrento");
addOption(document.drop_list.Dest,"CTA", "Sicily");
addOption(document.drop_list.Dest,"IZM", "Turkey");
addOption(document.drop_list.Dest,"MIR", "Tunisia");
}
if(document.drop_list.origin.value == 'ORK'){
addOption(document.drop_list.Dest,"LPA", "Gran Canaria");
addOption(document.drop_list.Dest,"ACE", "Lanzarote");
addOption(document.drop_list.Dest,"LIS", "Lisbon");
addOption(document.drop_list.Dest,"IZM", "Turkey");
}
if(document.drop_list.origin.value == 'SNN'){
addOption(document.drop_list.Dest,"ACE", "Lanzarote");
addOption(document.drop_list.Dest,"IZM", "Turkey");
}

if(document.drop_list.origin.value == 'NOC'){
addOption(document.drop_list.Dest,"ACE", "Lanzarote");
}


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

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;
	
	if(value=="zzz"){
	optn.setAttribute("selected","selected");}


	selectbox.options.add(optn);
}