var no = 30;		// snow number
var speed = 15;		// smaller number moves the snow faster
var snowflake =	"http://www.brigademodels.co.uk/Graphics/snow.gif";

var ns4up = (document.layers) ? 1 : 0;		// browser sniffer
var ie4up = (document.all) ? 1 : 0;
var dx, xp, yp;								// coordinate and position variables
var am, stx, sty;							// amplitude and step variables
var i, doc_width = 800, doc_height = 600;

function snowSetup ()
{
	if (ns4up)
	{
		doc_width = self.innerWidth;
		doc_height = self.innerHeight;
	} // if
	else if (ie4up)
	{
		doc_width = document.body.clientWidth;
		doc_height = document.body.clientHeight;
	} // else if

	dx = new Array ();
	xp = new Array ();
	yp = new Array ();
	am = new Array ();
	stx = new Array ();
	sty = new Array ();

	for (i = 0; i < no; ++ i)
	{  
		dx[i] = 0;                        // set coordinate variables
		xp[i] = Math.random()*(doc_width-50);  // set position variables
		yp[i] = Math.random()*doc_height;
		am[i] = Math.random()*20;         // set amplitude variables
		stx[i] = 0.02 + Math.random()/10; // set step variables
		sty[i] = 0.7 + Math.random();     // set step variables

		if (ns4up)
		{                      // set layers
			if (i == 0)
			{
				document.write("<layer name=\"dot"+ i +"\" left=\"15\" ");
				document.write("top=\"15\" visibility=\"show\"><img src=\"");
				document.write(snowflake + "\" border=\"0\"></layer>");
			}
			else
			{
				document.write("<layer name=\"dot"+ i +"\" left=\"15\" ");
				document.write("top=\"15\" visibility=\"show\"><img src=\"");
				document.write(snowflake + "\" border=\"0\"></layer>");
			}
		}
		else if (ie4up)
		{
			if (i == 0)
			{
				document.write("<div id=\"dot"+ i +"\" style=\"POSITION: ");
				document.write("absolute; Z-INDEX: "+ i +"; VISIBILITY: ");
				document.write("visible; TOP: 15px; LEFT: 15px;\"><img src=\"");
				document.write(snowflake + "\" border=\"0\"></div>");
			}
			else
			{
				document.write("<div id=\"dot"+ i +"\" style=\"POSITION: ");
				document.write("absolute; Z-INDEX: "+ i +"; VISIBILITY: ");
				document.write("visible; TOP: 15px; LEFT: 15px;\"><img src=\"");
				document.write(snowflake + "\" border=\"0\"></div>");
		    }
		}
	}
} // snowSetup

// Netscape main animation function
function snowNS()
{ 
	for (i = 0; i < no; ++ i)	// iterate for every dot
	{
		yp[i] += sty[i];
		if (yp[i] > doc_height-50)
		{
			xp[i] = Math.random()*(doc_width-am[i]-30);
			yp[i] = 0;
			stx[i] = 0.02 + Math.random()/10;
			sty[i] = 0.7 + Math.random();
			doc_width = self.innerWidth;
			doc_height = self.innerHeight;
		}
		dx[i] += stx[i];
		document.layers["dot"+i].top = yp[i];
		document.layers["dot"+i].left = xp[i] + am[i]*Math.sin(dx[i]);
	}
	setTimeout("snowNS()", speed);
}

// IE main animation function
function snowIE()
{  
	for (i = 0; i < no; ++ i)	// iterate for every dot
	{	
		yp[i] += sty[i];
		if (yp[i] > doc_height-50)
		{
			xp[i] = Math.random()*(doc_width-am[i]-30);
			yp[i] = 0;
			stx[i] = 0.02 + Math.random()/10;
			sty[i] = 0.7 + Math.random();
			doc_width = document.body.clientWidth;
			doc_height = document.body.clientHeight;
		}
		dx[i] += stx[i];
		document.all["dot"+i].style.pixelTop = yp[i];
		document.all["dot"+i].style.pixelLeft = xp[i] + am[i]*Math.sin(dx[i]);
	}
	setTimeout ("snowIE()", speed);
}