var no = 50;
var speed = 1;
var s, x, y, sn, cs;
var a, r, cx, cy;
var doc_width = 800, doc_height = 600;
doc_width = document.documentElement.clientWidth;
doc_height = document.documentElement.clientHeight;
x = new Array();
y = new Array();
r = new Array();
cx = new Array();
cy = new Array();
s = 8;
function initRain() {
	for(var i=0; i<50; i++){
		a = 6;
		r[i] = 1;
		sn = Math.sin(a);
		cs = Math.cos(a);
		cx[i] = Math.random() * doc_width + 1;
		cy[i] = Math.random() * doc_height + 1;
		x[i] = r[i] * sn + cx[i];
		y[i] = cy[i];
	}
}
function makeRain() {
	for(var i=0; i<50; i++){
		r[i] = 1;
		cx[i] = Math.random() * doc_width + 1;
		cy[i] = 1;
		x[i] = r[i] * sn + cx[i];
		y[i] = r[i] * cs + cy[i];
	}
}
function updateRain(i) {
	r[i] += s;
	x[i] = r[i] * sn + cx[i];
	y[i] = r[i] * cs + cy[i];
}
function raindrop() {
	for (var i = 0; i < no; i++) {
		updateRain(i);
		if ((x[i] <= 1) || (x[i] >= (doc_width - 20)) || (y[i] >= (doc_height - 20))) {
			makeRain();
			doc_width = document.documentElement.clientWidth;
			doc_height = document.documentElement.clientHeight;
		}
		raindropElem =document.getElementById("dot"+i); 
		raindropElem.style.top = y[i]+'px';
		raindropElem.style.left = x[i]+'px';
	}
	setTimeout("raindrop()", speed);
}