// window.onerror=processError;

		// variables used to change selection when "===" selected
		var nModelPrevSelected = new Number(0);
		var nMakePrevSelected = new Number(0);

		var makesName = new Array();
		// used as a cross reference table for name and number
		// the following are used as a 2D table for makes and models
		var makes = new Array();
		var models = new Array();
		// load the arrays and construct the selections on the page
		function initDocument()
		{
		initCars();
		fillMakeSelect();
		//fillModelSelect( "1" );     
		delayModelSelect(0);  
		}
		// create car make objects and fill arrays
		function K( makenumber, make )
		{
		makesName[make] = new MakesName(make,makenumber);
		makes[makenumber] = new Make( make,makenumber );
		}
		// make name constructor
		function MakesName( makeName,makeNumber )
		{
		this.makeNumber = makeNumber;
		}
		// make constructor
		function Make( makeName,makeNumber )
		{
		this.makeName = makeName;
		this.makeNumber = makeNumber;
		// create array associated with makes
		this.models = new Array();
		}
		// construct make selection on page
		function fillMakeSelect(  )
		{

		document.QuickForm.mknm.options.selectedIndex = 0;
		// init selection index
		document.QuickForm.mknm.options.length = 1;
		// clear select

		// fill selection with makes
		var i = 0;
		for ( makesIdx in makes )
		{
		var aMake = makes[makesIdx];
		if (aMake.makeName != undefined) {
  		document.QuickForm.mknm.options[ i ] = new Option( aMake.makeName, aMake.makeName );
  		i++;
	  }
		}
		document.QuickForm.mknm.options[ i ] = new Option( "===============" , "" );

		document.QuickForm.mknm.options[ 0 ].selected = true;
		// select first item
		}
		// create car model objects and fill arrays
		function D( makeNumber, model )
		{
		var modelObj = new Model( model, makeNumber);
		makes[makeNumber].models[model] = modelObj;
		}
		// model constructor
		function Model( model,makeNumber )
		{
		this.modelName = model;
		this.makeNumber = makeNumber;
		}
		// construct model selection on page
		function fillModelSelect( makeNbr )
		{
		document.QuickForm.mdnm.options.selectedIndex = 0;
		document.QuickForm.mdnm.options.length = 1; 
		var selectedModels;

		selectedModels = (makes[makeNbr].models);
		var i=0;
		document.QuickForm.mdnm.options[ i ] = new Option( "Select a Model" , "Select a Model" );
		i++;
		for ( aModelIdx in selectedModels )
		{
		aModel = selectedModels[ aModelIdx ];
		if (aModel.modelName != undefined) {
  		document.QuickForm.mdnm.options[ i ] = new Option( aModel.modelName, aModel.modelName );
  		i++;
  	}
		}
		document.QuickForm.mdnm.options[ i ] = new Option( "===============" , "" );

		document.QuickForm.mdnm.options[ 0 ].selected = true;
		
		if(psMd != 0){document.QuickForm.mdnm.options[psMd].selected = true;psMd=0;}
		}
		// when make selected fill model selection
		function selectedMake( aSelectedMake )
		{
		var selectedIdx = aSelectedMake.selectedIndex;
		var selectedMakeName = (aSelectedMake.options[ selectedIdx ]).value;

		var i = 0;
		for (aIdx in makesName)
		{
		if (aIdx == selectedMakeName)
		i++;
		}

		if (i == 0)
		{
		Populate(document.QuickForm.mknm,0);
		}		
		else
		{
		var makeNBR = makesName[selectedMakeName].makeNumber;
		// use cross reference table to get makeintid
		fillModelSelect( makeNBR );	
		}
		}
		function PopulateClient(listBox, prevSelected)
		{
		var selectedValue = new String(listBox.options[listBox.selectedIndex].value);

		with (document.QuickForm)
		{                       
		if(listBox.selectedIndex != listBox.options.length-1)
		selectedMake(listBox);
		else
		{
		listBox.options[prevSelected].selected = true;
		selectedMake(listBox);
		}
		}
		}

		// check user selection on model selection list
		function validateModel()
		{
		with (document.QuickForm)
		{
		if(mdnm.options[mdnm.selectedIndex].value == "")
		mdnm.options[nModelPrevSelected].selected = true;
		}
		}

		function ValidateUsed() {
			with (document.QuickForm) {
				if (zc.value == "" || zc.value.length < 5)  {
					alert("Please enter a valid five-digit ZIP code to find cars in your area.");
					return false;
				}
				else return true;

			}
		}
		
		function submitUsedForm() {
			var zipEntered = ValidateUsed();
			if (zipEntered){
				document.QuickForm.submit();
			}
		}
		
		function processError()
		{
		with (document.QuickForm)
		{
		if(mknm.options[mknm.selectedIndex].value != "")
		{
		Populate(mknm,0);
		}
		else
		mknm.options[0].selected = true;			 
		}
		return true;
		}
		
		var psMd = 0;
		
function delayModelSelect(n){
	if(n == 0){
	window.setTimeout('delayModelSelect(1)', 100);
	} else if(n == 1){
		psMd = document.getElementById('usedmd').options.selectedIndex;
		window.setTimeout('fillModelSelect('+makesName[document.getElementById('usedmk').options[document.getElementById('usedmk').options.selectedIndex].value].makeNumber+')', 200);
		}
}