Snefnug på skærmen

Hej Eksperter.

Jeg har det lige nu på min hjemmeside sådan at der kommer lidt sne ned over min side. Men alle snefnugene stopper ca. 1 cm. før siden stopper. Hvorfor?

html-siden:
<SCRIPT LANGUAGE="JavaScript" src="/grafik/juletema/snow.js">
</script>

snow.js:
var no = 5; // snow number
var speed = 30; // smaller number moves the snow faster
var snowflake = "/grafik/juletema/sne.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 = 400, doc_height = 500;
if (ns4up) {
  doc_width = self.innerWidth;
  doc_height = self.innerHeight;
} else if (ie4up) {
  doc_width = 500;
  doc_height = 500;
}
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>");
    }
  }
}
function snowNS() {  // Netscape main animation function
  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);
}

function snowIE() {  // IE main animation function
  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);
}

if (ns4up) {
  snowNS();
} else if (ie4up) {
  snowIE();
}