//JScript File

var TRANSITION_SPEED = 500;
var IMAGE_SWITCH_INTERVAL = 5000;


var imgNum; 

function opacity(id, opacStart, opacEnd, millisec) 
{
	//speed for each frame 
	var speed = Math.round(millisec / 100); 
	var timer = 0;


	//determine the direction for the blending, if start and end are the same nothing happens 
	if(opacStart > opacEnd) { 
		for(i = opacStart; i >= opacEnd; i--) { 
			setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed)); 
			timer++; 
		} 
	} else if(opacStart < opacEnd) { 
		for(i = opacStart; i <= opacEnd; i++) 
		{ 
			setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed)); 
			timer++; 
		} 
	} 
} 

//change the opacity for different browsers 
function changeOpac(opacity, id) { 
	var object = document.getElementById(id).style; 
	object.opacity = (opacity / 100); 
	object.MozOpacity = (opacity / 100); 
	object.KhtmlOpacity = (opacity / 100); 
	object.filter = "alpha(opacity=" + opacity + ")"; 
}

function bannerSwitch()
{
	var home = document.getElementById('HomeIcon');
	var app1 = document.getElementById('App1Icon');
	var app2 = document.getElementById('App2Icon');
	var app3 = document.getElementById('App3Icon');
	var bp = document.getElementById("Banner_Pointer");
	
	if(imgNum == 1)
	{
		imgNum = 2;
		opacity('See',100, 0, TRANSITION_SPEED);
		opacity('Main',100, 0,  TRANSITION_SPEED);
		opacity('App1',0, 100, TRANSITION_SPEED);
		home.src = 'images/home/select_arrow.png';
		app1.src = 'images/home/select_arrow.png';
		bp.style.marginLeft = "415px";
	}
	else if(imgNum == 2)
	{
		imgNum = 3;
		opacity('App1',100, 0, TRANSITION_SPEED);
		opacity('App2',0, 100, TRANSITION_SPEED);
		app1.src = 'images/home/select_arrow.png';
		app2.src = 'images/home/select_arrow.png';
		bp.style.marginLeft = "477px";
	}
	else if(imgNum == 3)
	{
		imgNum = 4;
		opacity('App2',100, 0, TRANSITION_SPEED);
		opacity('App3',0, 100, TRANSITION_SPEED);
		app2.src = 'images/home/select_arrow.png';
		app3.src = 'images/home/select_arrow.png';
		bp.style.marginLeft = "539px";

	}
	else
	{
		imgNum = 1;
		opacity('App3',100, 0, TRANSITION_SPEED);
		opacity('Main',0, 100, TRANSITION_SPEED);
		opacity('See',0, 100, TRANSITION_SPEED);
		app3.src = 'images/home/select_arrow.png';
		home.src = 'images/home/select_arrow.png';
		bp.style.marginLeft = "354px";
	}
}

function startShow()
{
	imgNum = 1;
	
	changeOpac(100,'Main');
	changeOpac(100,'See');
	changeOpac(0,'App1');
	changeOpac(0,'App2');
	changeOpac(0,'App3');
	
	setInterval('bannerSwitch();',IMAGE_SWITCH_INTERVAL);
}