// Actions
	var move_star = false;
	
	// Mouse
	var Mouse_x;
	var Mouse_y;
	
	// Neutral stars
	var total_neutral_stars = 100;
	
	// New star
	function Star (id, name, x, y)
	{
		this.id = id;
		this.name = name;
		this.x = x;
		this.y = y;
		this.display = function ()
		{
			document.write("<img src=\"../images/star.gif\" id=\"star\" style=\"background-color: #FF9900; top: " + this.y + "px; left: " + this.x + "px;\" onmouseover=\"return displayStarName (" + this.id + ");\" onmouseout=\"return hideStarName ();\">");
		}
	}
	
	// Star on this position
	function starOnPosition (x, y)
	{
		for (var i = 0; i < stars.length; ++i)
			if ((stars[i].x == x && stars[i].y == y)
				|| (stars[i].x + 1 == x && stars[i].y == y)
				|| (stars[i].x == x && stars[i].y + 1 == y)
				|| (stars[i].x + 1 == x && stars[i].y + 1 == y))
				return true;
		return false;
	}
	
	// Start galaxy
	function startGalaxy ()
	{
		window.setInterval ("moveGalaxy ();", 3000);
		layer_sky.onclick = setStar;
	}
	
	// Create artificial stars
	function createGalaxy ()
	{
		var x;
		var y;
		
		if (!layer_sky)
			return;

		for (var i = 0; i < total_neutral_stars; ++i)
		{
			x = Math.floor ((layer_sky.offsetWidth - 5) * Math.random());
			y = Math.floor (layer_sky.offsetHeight * Math.random());
			
			document.write ("<img id=\"star" + i + "\" class=\"star_neutral\" src=\"../images/star_neutral.gif\" style=\"background-color: #FFFFFF; top: " + y + "px; left: " + x + "px;\">");
		}
	}
	
	// Make neutral stars move
	function moveGalaxy ()
	{
		var star_id = Math.floor (total_neutral_stars * Math.random ());
		var layer_star = document.getElementById("star" + star_id);
		var x;
		var y;
		
		if (!layer_sky || !layer_star)
			return;
		x = Math.floor ((layer_sky.offsetWidth - 5) * Math.random ());
		y = Math.floor (layer_sky.offsetHeight * Math.random ());
		
		layer_star.style.top = y + "px";
		layer_star.style.left = x + "px";
	}
	
	// Locate star
	function locateStar (id)
	{
		if (!layer_locate)
			return;
			
		layer_locate.style.left = (stars[id].x - 2) + "px";
		layer_locate.style.top = (stars[id].y - 2) + "px";
		layer_locate.style.visibility = "visible";
	}
	
	// Move star
	function moveStar ()
	{
		if (document.newstar_form.newstar_star_name.value == "" || document.newstar_form.newstar_star_name.value == "My Star")
		{
			// Error
			var layer_error = document.getElementById("error");

			setError ("Please name your star.");
			return;
		}
		
		if (!layer_sky)
			return;
		
		move_star = true;
		layer_sky.style.cursor = "crosshair";
	}
	
	// Set star
	function setStar (e)
	{
		if (!layer_sky || !move_star)
			return;
		
		if (starOnPosition (Mouse_x, Mouse_y))
		{
			setError ("Can't hang your star up there.");
			return;
		}
		if (sky_height == 0 || sky_width == 0)
		{
			setError ("Unexpected error");
			return;
		}
		
		var form_star = document.newstar_form;
		
		move_star = false;
		layer_sky.style.cursor = "default";
		
		form_star.newstar_star_x.value = Mouse_x;
		form_star.newstar_star_y.value = Mouse_y;
		form_star.newstar_size_x.value = sky_width;
		form_star.newstar_size_y.value = sky_height;
		form_star.submit ();
	}

	// Set error message
	function setError (message)
	{
		if (!layer_error)
			return;

		layer_error.innerHTML = "<span>" + message + "</span>";
		setTimeout ("document.getElementById('error').innerHTML = '';", 3000);
	}
	
	// Save mouse position
	function getPosition (mouse)
	{
		Mouse_x = (navigator.appName.substring(0,3) == "Net") ? mouse.pageX : event.x + document.body.scrollLeft;
		Mouse_y = (navigator.appName.substring(0,3) == "Net") ? mouse.pageY : event.y + document.body.scrollTop;
	}
	
	// Display star name
	function displayStarName (id)
	{
		if (!layer_star_label)
			return;
	
		layer_star_label.style.color = "#FF9900";
		layer_star_label.style.backgroundColor = "#003366";
		if (stars[id].x > sky_width / 2)
		{
			layer_star_label.style.right = (sky_width - Mouse_x + 12) + "px";
			layer_star_label.style.left = "";
		}
		else
		{
			layer_star_label.style.left = (Mouse_x + 18) + "px";
			layer_star_label.style.right = "";
		}
		layer_star_label.style.top = (Mouse_y + 5) + "px";
		layer_star_label.innerHTML = stars[id].name;
	}
	
	// Hide star name
	function hideStarName ()
	{
		if (!layer_star_label)
			return;
			
		layer_star_label.innerHTML = "";
		layer_star_label.style.top = "-10px";
	}
	
	// Start event detection
	document.onmousemove = getPosition;