// JavaScript Document

function getWindowHeight() {
	var windowHeight = 0;
	if (typeof(window.innerHeight) == 'number') {
		windowHeight = window.innerHeight;
	}
	else {
		if (document.documentElement && document.documentElement.clientHeight) {
			windowHeight = document.documentElement.clientHeight;
		}
		else {
			if (document.body && document.body.clientHeight) {
				windowHeight = document.body.clientHeight;
			}
		}
	}
	return windowHeight;
}

function setContent(id) {
	if (document.getElementById) {
		var windowHeight = getWindowHeight();
		if (windowHeight > 0) {
			var contentElement = document.getElementById(id);
			var contentHeight = contentElement.offsetHeight;
			if (windowHeight - contentHeight > 0) {
				contentElement.style.position = 'relative';
				contentElement.style.top = ((windowHeight / 2) - (contentHeight / 2)) + 'px';
			}
			else {
				contentElement.style.position = 'static';
			}
		}
	}
}

function fadeOut(id, time) {
	target = document.getElementById(id);
	alpha = 100;
	timer = (time*1000)/50;
	var i = setInterval(
			function() {
				if (alpha <= 0)	clearInterval(i);
				setAlpha(target, alpha);
				alpha -= 2;
			}, timer);
}

function fadeIn(id, time) {
	target = document.getElementById(id);
	alpha = 0;
	timer = (time*1000)/50;
	var i = setInterval(
			function() {
				if (alpha >= 100)
					clearInterval(i);
				setAlpha(target, alpha);
				alpha += 2;
				target.style.visibility = "visible";
			}, timer);
}

function setAlpha(target, alpha) {
	target.style.filter = "alpha(opacity="+ alpha +")";
	target.style.opacity = alpha/100;
}