// global object
var t = { 'timer' : null, 'count' : 1, index : 0 }

t.imgs = [
    '/images/home-bg/doctors-bg.jpg',
    '/images/home-bg/guy-beach.jpg',
    '/images/home-bg/guy-garden.jpg',
    '/images/home-bg/guy-hands.jpg',
    '/images/home-bg/guy-pensive.jpg'
    ];

function setOpacity(elem, opacity)
{
    // set IE opacity
	elem.style.filter = 'alpha(opacity=' + (opacity * 100) + ')';
	// set DOM opacity
	elem.style.opacity = opacity; // (opacity == 1 ? 0.9999999 : opacity);
}

function step()
{
    t.count -= (1 / t.resolution);
    
    if (t.count < (1 / t.resolution))
    {
        // make sure the new object is fully visible and the old object is invisible
        setOpacity(t.newobj, 1);
                
        // hide the old object
        // t.obj.style.visibility = 'hidden';
        setOpacity(t.obj, 0);
                
        // clear the timer
		clearInterval(t.timer);
		t.timer = null;
	    setTimeout("transition()", 4000);
    }
    else
    {
        setOpacity(t.obj, t.count);
	    setOpacity(t.newobj, 1 - t.count);
	    t.newobj.style.visibility = 'visible';
	}
}

function transition()
{
    if (t.timer == null) 
    {
        t.obj = t.divs[t.index];
        
        t.index++;
	    if (t.index >= t.divs.length) 
	    {
		    t.index = 0;
	    }
        
        t.newobj = t.divs[t.index];
    
        // reset the counter
        t.count = 1;    
        t.timer = setInterval("step()", t.length / t.resolution);
    }
}

function initialize()
{
    t.divs = [];
    t.length = 2 * 1000;
    t.resolution = 2 * 20;
    
    var parentNode = document.getElementById('content');
    
    for (var i = 0; i < t.imgs.length; i++)
    {
        t.divs[i] = document.createElement('div');
        t.divs[i].style.position = 'absolute';
        t.divs[i].style.height = '326px';
        t.divs[i].style.width = '918px';
        t.divs[i].style.backgroundImage = 'url(' + t.imgs[i] + ')';
        t.divs[i].style.backgroundRepeat = 'no-repeat';
        t.divs[i].style.backgroundPosition = 'top right';
        t.divs[i].style.zIndex = '2';
        t.divs[i].style.visibility = (i == 0) ? 'visible' : 'hidden';
        parentNode.insertBefore(t.divs[i], parentNode.firstChild); 
    }

    setTimeout("transition()", 4000);   
}