<script type="text/javascript">
var size = 35,
    no = 10,
    speed = 150,
    snowflake = '<div style="font-family:serif;font-size:' + size + 'pt;color:White;">*</div>',
    doc_width = document.body.clientWidth,
    doc_height = document.body.clientHeight,
    dx = new Array(),
    xp = new Array(),
    yp = new Array(),
    stx = new Array();

for (i = 0; i < no; i ++) {
    dx[i] = Math.random() * 40
    xp[i] = Math.random() * doc_width
    yp[i] = Math.random() * doc_height
    document.write('<div id="dot1' + i + '" style="POSITION:absolute;Z-INDEX:' + i + '">' + snowflake + '</div>');
}

function snow() {
    for(i = 0; i < no; i ++) {
        yp[i] += 0.9 + Math.random()

        if (yp[i] > doc_height) {
            xp[i] = Math.random() * (doc_width) - 100
            yp[i] = 0
        }
        
        dx[i] += 0.08 + Math.random() / 10
        document.all["dot1" + i].style.top = yp[i]
        document.all["dot1" + i].style.left = xp[i] + 20 * Math.sin(dx[i] + 30)
    }
}

setInterval(snow, speed);
</script>