var init_js_environment = window.onload;
window.onload = function()
{
	if (typeof init_js_environment == 'function')
	{
		init_js_environment();
	}
	init();
}

var image;
var new_image;
function init()
{
	var imageContainer = document.getElementById('imageContainer');

	if(imageContainer)
	{
		image = findDescendant(imageContainer, 'img');
		if(image)
		{
			setInterval('reloadImage("' + image.offsetHeight + '")', 7000);
		}
	}
}

function reloadImage(size)
{
	loadXmlHttp(location.pathname + '?only_header_image=1&size=' + size, reloadImageCallback, '', 'get', null, 1);
}

function reloadImageCallback(response)
{
	new_image = document.createElement('img');
	new_image.style.opacity = 0;
	if(document.all)
	{
		new_image.style.filter = 'alpha(opacity=' + 0 + ')';
	}
	new_image.style.left = 0;
	new_image.src = response.responseText;
	image.parentNode.appendChild(new_image);
	img = new_image;
	fadeIn();
}

var img 	 = false;
var step 	 = 5;  // %
var interval = 10; // ms
function fadeIn(opacity)
{
	if(!img)
	{
		return;
	}
	if(opacity == undefined)
	{
		opacity = 0;
	}
	img.style.opacity = opacity / 100;
	if(document.all)
	{
		new_image.style.filter = 'alpha(opacity=' + opacity + ')';
	}
	if(opacity < 100)
	{
		opacity += step;
		setTimeout('fadeIn(' + opacity + ')', interval);
	}
	else
	{
		img.parentNode.removeChild(image);
		image = new_image;
	}
}