var no = 25; 								// number of snowflakes
var speed = 10; 							// the smaler, the faster move snowflakes
var snowflake = "snow.gif";					// picture source
var ns4b = (document.layers) ? 1 : 0;		// Netscape4.x
var b4up = (document.all) ? 1 : 0;			// MSIE4, Opera5, Netccape5
var dx, xp, yp;								// coordinate and position variables
var am, stx, sty;							// amplitude and step variables
var snowobj;
var i, doc_width = 800, doc_height = 600;	// 800x600 screen-default

if (ns4b) {
	doc_width  = self.innerWidth;
	doc_height = self.innerHeight;
} else if (b4up) {
	doc_width  = document.body.clientWidth;
	doc_height = document.body.clientHeight;
} else {
    doc_width  = window.innerWidth;
    doc_height = window.innerHeight;
	b4up = 1;
}// if

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

for (i=0; i<no; ++i) {  					// iterate for every snowflake
	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 (ns4b) {								// set layers
		document.write("<LAYER NAME=\"flake"+ i +"\" LEFT=\"15\" TOP=\"15\" VISIBILITY=\"show\"><IMG SRC=\""+ snowflake +"\" BORDER=0></LAYER>");
	} else if (b4up) {
		document.write("<DIV ID=\"flake"+ i +"\" STYLE=\"position:absolute; z-index:"+ i +"; visibility:visible; top:15px; left:15px;\"><IMG SRC=\""+ snowflake +"\" BORDER=0></DIV>");
		snowobj[i] = eval (document.getElementById("flake"+i).style);
	}//if
}//for

function snowNS() {  						// Netscape4 main animation function
	for (i=0; i<no; ++i) {  				// iterate for every snowflake
		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();
		}//if
		dx[i] += stx[i];
		document.layers["flake"+i].top = yp[i];
		document.layers["flake"+i].left = xp[i] + am[i]*Math.sin(dx[i]);
	}//for
	setTimeout("snowNS()", speed);
}//snowNS

function snowDocument() {  					// MSIE4, Opera5, Netscape5 main animation function
	for (i=0; i<no; ++i) {					// iterate for every flake
		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();
		}//if
		dx[i] += stx[i];
		snowobj[i].top  = yp[i];
		snowobj[i].left = xp[i] + am[i]*Math.sin(dx[i]);
	}//for
	setTimeout("snowDocument()", speed);
}//snowDocument

if (ns4b) {									// Netscape4
	snowNS();
} else if (b4up) {							// MSIE4, Opera5, Netscape5
	snowDocument();
}//if