var queryString=new Object();

function init() {
  ClearSelection(document.carSelect.year," --- Step 1: Select A Year -- ");
  ClearSelection(document.carSelect.make," --- Step 2: Select A Make -- ");
  ClearSelection(document.carSelect.model," --- Step 3: Select A Model -- ");
  var year="";
  var Selection=document.carSelect.year;
  for (year in cars) {
    Selection.options[Selection.options.length]=new Option(year,year,false,false);
  }
  Selection.options[0].selected=true;
  if (Selection.options.length==2) {
    Selection.options[1].selected=true;
    YearSelected();
  }
  document.carSelect.make.options[0].selected=true;
  document.carSelect.model.options[0].selected=true;
  processInput();
  if (queryString['make']) {
	var Makes=document.carSelect.make;
	for (var i=0; i < Makes.options.length; i++) {
		if (Makes.options[i].value==queryString['make']) {
			Makes.options[i].selected=true;
		}
	}
  	MakeSelected();
  }
}

function processInput() {
	var string=window.location.search;
	if (string) {
		if (string.length > 1) {
			string=string.substring(1, string.length);
		}
		for (var i=0; i < string.split("&").length; i++) {
			var key=unescape(string.split("&")[i].split("=")[0]);
			var value=unescape(string.split("&")[i].split("=")[1]);
			queryString[key]=value;
		}
	}
}

function verify() {
  var year=getYear();
  var model=getModel();
  var make=getMake();
  var mesg="";
  if (year == "") {
    mesg=mesg+"You must select a year!\n";
  }
  if (make == "") {
    mesg=mesg+"You must select a make!\n";
  }
  if (model == "") {
    mesg=mesg+"You must select a model!\n";
  }
  if (mesg != "") {
    mesg="Error!\n\n"+mesg;
    alert(mesg);
    return false;
  } else {
    return true;
  }
}

function ClearSelection(Selection, newOption) {
  Selection.length=0;
  Selection.options[0]=new Option(newOption, '',true,true);
}

function getYear() {
  var Years=document.carSelect.year;
  for (var i=0; i < Years.options.length; i++) {
    if (Years.options[i].selected) {
      return Years.options[i].value;
    }
  }
}

function getMake() {
  var Makes=document.carSelect.make;
  for (var i=0; i < Makes.options.length; i++) {
    if (Makes.options[i].selected) {
      return Makes.options[i].value;
    }
  }
}

function getModel() {
  var Models=document.carSelect.model;
  for (var i=0; i < Models.options.length; i++) {
    if (Models.options[i].selected) {
      return Models.options[i].value;
    }
  }
}

function YearSelected() {
  ClearSelection(document.carSelect.make," --- Step 2: Select A Make -- ");
  ClearSelection(document.carSelect.model," --- Step 3: Select A Model -- ");
  var make="";
  var year=getYear();
  for (make in cars[year]) {
    var Selection=document.carSelect.make;
    Selection.options[Selection.options.length]=new Option(make, make,false,false);
  }
  document.carSelect.make.options[0].selected=true;
}

function MakeSelected() {
  ClearSelection(document.carSelect.model," --- Step 3: Select a Model -- ");
  var make=getMake();
  var year=getYear();
  var model="";
  for (model in cars[year][make]) {
    var Selection=document.carSelect.model;
    Selection.options[Selection.options.length]=new Option(model, model,false,false);
  }
  document.carSelect.model.options[0].selected=true;
}

function ModelSelected() {
  var make=makeFiles(getMake());
  var year=getYear();
  var model=makeFiles(getModel());
  document.carSelect.action='/nvi/'+make+'_'+model+'.html';
}

function makeFiles(word) {
	word=word.replace(/\ /g,"_");
	word=word.replace(/\-/g,"_");
	word=word.replace(/\"/g,"_");
	word=word.replace(/\'/g,"_");
	return word;
}