function changeModels(id) {

	if (id) {
	
		var ModelList = modelNames[document.form1.smake.options[document.form1.smake.selectedIndex].value];

 		clearOptions(document.form1.smodel);
 	 	var newModels = ModelList.split(',');
 	 	for (var i = 0; i < newModels.length; i++)	{
 	 		addOption(document.form1.smodel, newModels[i]);
 	  	}
		document.form1.smodel.disabled = false;
  
  	} else {
		
		resetList();
		
	}
	
}

function resetList() 
{
		clearOptions(document.form1.smodel);
		addOption(document.form1.smodel,"choose");
		addOption(document.form1.smodel, "======");	
		document.form1.smodel.disabled = true;
}	

function clearOptions(list) {
    var i = 0;
    var o = list.options;

    for (i = o.length; i >= 0; --i)
		o[i] = null;
    list.disabled = true;
}

function addOption(list, text_in)	{
    var o = list.options;
    var nIdx;
	if (o.length < 0) {
		nIdx = 0;
	} else {
		nIdx = o.length;
	}	
		
	o[nIdx] = new Option(text_in);
	list.disabled = false;
}

function resetModelAddSelected(modelname) {
	clearOptions(document.form1.smodel);
	addOption(document.form1.smodel,modelname);
	addOption(document.form1.smodel, "======");
	var ModelList = modelNames[document.form1.smake.options[document.form1.smake.selectedIndex].value];
	var newModels = ModelList.split(',');
 	 	for (var i = 0; i < newModels.length; i++)	{
 	 		addOption(document.form1.smodel, newModels[i]);
 	  	}	
	document.form1.smodel.disabled = false;
}