Javascript ~ 雪景效果

　

(1)　預備雪花圖片一張 （可換上自己喜歡的圖片）　　

   image : snow.gif
(2)　請把以下程式放在 <body> 內的任何位置：
<script language="JavaScript1.2">

//更 改 以 下 檔 案 為 你 的 路 徑 圖 像 檔 案

var snowsrc="gsnow01.gif"

// 更 改 以 下 圖 像 的 數 目 為 你 喜 歡 的 設 定 值 

var no = 10;

var ns4up = (document.layers) ? 1 : 0; 
var ie4up = (document.all) ? 1 : 0;

var dx, xp, yp; 
var am, stx, sty; 
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; 
xp[i] = Math.random()*(doc_width-50); 
yp[i] = Math.random()*doc_height;
am[i] = Math.random()*20; 
stx[i] = 0.02 + Math.random()/10; 
sty[i] = 0.7 + Math.random(); 
if (ns4up) { 
if (i == 0) {
document.write("<layer name=\"dot"+ i +"\" left=\"15\" top=\"15\" visibility=\"show\"><a href=\"http://dynamicdrive.com/\"><img src='"+snowsrc+"' border=\"0\"></a></layer>");
} else {
document.write("<layer name=\"dot"+ i +"\" left=\"15\" top=\"15\" visibility=\"show\"><img src='"+snowsrc+"' border=\"0\"></layer>");
}
} else if (ie4up) {
if (i == 0) {
document.write("<div id=\"dot"+ i +"\" style=\"POSITION: absolute; Z-INDEX: "+ i +"; VISIBILITY: visible; TOP: 15px; LEFT: 15px;\"><a href=\"http://dynamicdrive.com\"><img src='"+snowsrc+"' border=\"0\"></a></div>");
} else {
document.write("<div id=\"dot"+ i +"\" style=\"POSITION: absolute; Z-INDEX: "+ i +"; VISIBILITY: visible; TOP: 15px; LEFT: 15px;\"><img src='"+snowsrc+"' 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()", 10);
}

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()", 10);
}

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

</script>