function makeModel() {
	this.makeEl = document.getElementById('make');
	this.makeFr = document.step1.make;
	this.modelEl = document.getElementById('model');
	this.modelFr = document.step1.model;
	this.arr_makes = new Array('Buick', 'GMC', 'Pontiac');
	this.arr_models = new Array(['Enclave', 'LaCrosse', 'Lucerne'], ['Canyon', 'Acadia', 'Yukon Hybrid', 'Sierra 1500', 'Yukon', 'Envoy Denali', 'Envoy', 'Yukon XL', 'Savana Cargo', 'Sierra Denali', 'Yukon Denali', 'Yukon XL Denali', 'Savana Passenger', 'Sierra 2500HD', 'Sierra 3500HD'], ['G3', 'G5', 'G6', 'G8', 'Solstice', 'Torrent', 'Vibe']);
	this.currentMake = '';
	
	this.makeEl.onchange = makeModel.prototype.checkValue(this);
	
	this.fPopMake = this.popMake;
}

makeModel.prototype.popMake = function() {
	this.makeFr[0] = new Option('-- Select --', '');
	for(var i = 0; i < this.arr_makes.length; i++) {
		this.makeFr[(i + 1)] = new Option(this.arr_makes[i], this.arr_makes[i]);
	}
}

makeModel.prototype.checkValue = function(object) { 
	return function() {
		object.currentMake = this.value;
		if(object.currentMake != '') {
			makeModel.prototype.changeModel(object);
		} else {
			makeModel.prototype.changeDisabled(object, 'disable');
			makeModel.prototype.emptyModel(object);
		}
	};
}

makeModel.prototype.changeModel = function(object) {
	var j = 0;
	switch(object.currentMake) {
		case 'Buick':
			j = 0;
			break;
		case 'GMC':
			j = 1;
			break;
		case 'Pontiac':
			j = 2;
			break;
	}
	
	makeModel.prototype.emptyModel(object);
	
	for(var i = 0; i < object.arr_models[j].length; i++) {
		if(i == 0) {
			object.modelFr[i] = new Option(object.arr_models[j][i], object.arr_models[j][i], true);
		}
		object.modelFr[i] = new Option(object.arr_models[j][i], object.arr_models[j][i]);
	}

	makeModel.prototype.changeDisabled(object, 'enable');
}

makeModel.prototype.changeDisabled = function(object, action) {
	if(action == 'enable' && object.modelEl.getAttribute('disabled')) {
		object.modelEl.removeAttribute('disabled');
	} else if(action == 'disable' && !object.modelEl.getAttribute('disabled')) {
		object.modelEl.setAttribute('disabled', 'disabled');
	}
}

makeModel.prototype.emptyModel = function(object) {	
	object.modelFr.options.length = 0;
}