var leftImages = new Array();
leftImages["pitbull"] = new Image(1000,550);
leftImages["pitbull"].src = "images/intro09/Pitbull.jpg";
leftImages["mastiff"] = new Image(1000,550);
leftImages["mastiff"].src = "images/intro09/Mastiff.jpg";
leftImages["ridgeback"] = new Image(1000,550);
leftImages["ridgeback"].src = "images/intro09/Ridgeback.jpg";
leftImages["k-9"] = new Image(1000,550);
leftImages["k-9"].src = "images/intro09/K-9.jpg";
leftImages["coyote"] = new Image(1000,550);
leftImages["coyote"].src = "images/intro09/Coyote.jpg";
leftImages["wolf"] = new Image(1000,550);
leftImages["wolf"].src = "images/intro09/Wolf.jpg";
leftImages["bulldog"] = new Image(1000,550);
leftImages["bulldog"].src = "images/intro09/Bulldog.jpg";

var leftIntervalID = "off";
var leftOpacity = "1.0";

function leftSwap(nextModel){
	document.getElementById("leftBottom").src = leftImages[nextModel].src;
	if(leftIntervalID !== 'off') return;
	var statement = "darkenModel('left');";
	leftIntervalID = setInterval(statement,30);
}
function darkenModel(side){
	var topImage = document.getElementById(side+"Top");
	if(side=="left") var opacity = leftOpacity;
	else var opacity = rightOpacity;
	switch(opacity){

		case '1.0':	topImage.style.filter = "alpha(opacity=80)";
					topImage.style.opacity = "0.8";
					topImage.style.MozOpacity = "0.8";
					topImage.style.KhtmlOpacity = "0.8";
					if(side=="left") leftOpacity = "0.8";
					else rightOpacity = "0.8";
					break;
		case '0.8':	topImage.style.filter = "alpha(opacity=60)";
					topImage.style.opacity = "0.6";
					topImage.style.MozOpacity = "0.6";
					topImage.style.KhtmlOpacity = "0.6";
					if(side=="left") leftOpacity = "0.6";
					else rightOpacity = "0.6";
					break;
		case '0.6':	topImage.style.filter = "alpha(opacity=40)";
					topImage.style.opacity = "0.4";
					topImage.style.MozOpacity = "0.4";
					topImage.style.KhtmlOpacity = "0.4";
					if(side=="left") leftOpacity = "0.4";
					else rightOpacity = "0.4";
					break;

		case '0.4':	topImage.style.filter = "alpha(opacity=20)";
					topImage.style.opacity = "0.2";
					topImage.style.MozOpacity = "0.2";
					topImage.style.KhtmlOpacity = "0.2";
					if(side=="left") leftOpacity = "0.2";
					else rightOpacity = "0.2";
					break;
		case '0.2':	topImage.style.filter = "alpha(opacity=0)";
					topImage.style.opacity = "0.0";
					topImage.style.MozOpacity = "0.0";
					topImage.style.KhtmlOpacity = "0.0";
					if(side=="left") leftOpacity = "0.0";
					else rightOpacity = "0.0";
					break;
		case '0.0': if(side=="left"){
						clearInterval(leftIntervalID);
						leftIntervalID = "off";
						document.getElementById("leftTop").src = document.getElementById("leftBottom").src;
						leftOpacity = "1.0";
					}
					else{
						clearInterval(rightIntervalID);
						rightIntervalID = "off";
						document.getElementById("rightTop").src = document.getElementById("rightBottom").src;
						rightOpacity = "1.0";
					}
					topImage.style.filter = "alpha(opacity=100)";
					topImage.style.opacity = "1.0";
					topImage.style.MozOpacity = "1.0";
					topImage.style.KhtmlOpacity = "1.0";
					break;
		default: if(side=="left"){
						clearInterval(leftIntervalID);
						leftIntervalID = "off";
						document.getElementById("leftTop").src = document.getElementById("leftBottom").src;
						leftOpacity = "1.0";
					}
					else{
						clearInterval(rightIntervalID);
						rightIntervalID = "off";
						document.getElementById("rightTop").src = document.getElementById("rightBottom").src;
						rightOpacity = "1.0";
					}
					topImage.style.filter = "alpha(opacity=100)";
					topImage.style.opacity = "1.0";
					topImage.style.MozOpacity = "1.0";
					topImage.style.KhtmlOpacity = "1.0";
	}
}