vallende_sneeuw2

Vallende sneeuw 2

Voor het javascript van Altan is een afbeelding nodig.

snow2a.gif

Rechtsklik op bovenstaand plaatje (het blauwe sterretje) en sla het op naar je harde schijf. Upload de afbeelding en de HTML-pagina met daarin de javascript-code. Natuurlijk kun je ook een ander plaatje kiezen. Verander dan in het script de naam van het plaatje.

De javascript-code:

Selecteer (Ctrl-A) en kopieer (Ctrl-C) het onderstaande script en plak (Ctrl-V) het binnen de body tags van een HTML-pagina.

<script language="JavaScript1.2">

<!-- Begin
var no = 15; // snow number
var speed = 9; // smaller number moves the snow faster
var snowflake = "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;
if (ns4up) {
doc_width = self.innerWidth;
doc_height = self.innerHeight;
} else if (ie4up) {
doc_width = document.body.clientWidth;
doc_height = document.body.clientHeight;
}
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();
}
// End -->
</script>

Met java applets kun je ook vallende sneeuw creëren. Kijk maar bij Tutorials: de Alcsnow-applet en de Snow-applet.