js浮动图片的动态效果_javascript技巧

 代码如下:






var step = 1; // 移动的像素
var y = -1; // 垂直移动的方向，-1表示向上，1表示向下
var x = 1; // 水平移动的方向，-1表示向左，1表示向右
function myFloat()
{
var img = document.getElementById("myImg");
// 获取图片和当前浏览器窗口上边距，由于img.style.top获取的值带px单位
var top = img.style.top.replace("px", "");
// top = top - 100;
// img.style.top = top + "px";
// 获取图片和当前浏览器窗口左边距
var left = img.style.left.replace("px", "");
// left = left - 100;
// img.style.left = left + "px";
// 上下移动
if(top <= 0)
{
y = 1;
}
if(top >= document.body.clientHeight)
{
y = -1;
}
top = (top*1) + (step * y);
img.style.top = top + "px";
// 左右移动
if(left <= 0)
{
x = 1;
}
// alert(img.clientWidth);
if(left >= (document.body.clientWidth - img.clientWidth))
{
x = -1;
}
left = (left*1) + (step * x);
img.style.left = left + "px";
setTimeout("myFloat()", 20);
}



style="position: absolute; left: 500px; top: 400px; border: solid 1px black;" />



另一种的实现方式
代码如下:





var pos = 10;
function toueme() {
document.getElementById("toubiao").style.display = "none";
}
function initArray() {
this.length = initArray.arguments.length;
for (var i = 0; i < this.length; i++) {
this[i] = initArray.arguments[i];
}
}
var col = new initArray("4b", "5b", "8b", "8b");
col[0] = "yellow";
col[1] = "coral";
col[2] = "orange";
col[3] = "red";
col[4] = "greenyellow";
col[5] = "lime";
col[6] = "turquoise";
col[7] = "coral";
col[8] = "blueviolet";
col[9] = "violet";
function chgCol() {
pos++;
if (pos < 0 || pos > 9) {
pos = 0;
}
document.bgColor = col[pos];
setTimeout("chgCol()", 500);
}



style="Z-INDEX: 100;
LEFT: 12px;
WIDTH: 159px;
POSITION: absolute;
TOP: 143px;
HEIGHT: 161px;
visibility: visible;">


src="https://www.gxlcms.com/Uploads/close.gif"
width=84 height=11 hspace="6" border=0>






var xPos = 0;
var yPos = 0;
var step = 3;
var delay = 100;
var height = 0;
var Hoffset = 0;
var Woffset = 0;
var yon = 0;
var xon = 0;
var pause = true;
var interval;
img1.style.top = yPos;
function changePos()
{
width = document.body.clientWidth; //获取浏览器的宽度
height = document.body.clientHeight; //获取浏览器的高度
Hoffset = img1.offsetHeight;
Woffset = img1.offsetWidth;
img1.style.left = xPos + document.body.scrollLeft;
img1.style.top = yPos + document.body.scrollTop;
if (yon)
{yPos = yPos + step;}
else
{yPos = yPos - step;}
if (yPos < 0)
{yon = 1;yPos = 0;}
if (yPos >= (height - Hoffset))
{yon = 0;yPos = (height - Hoffset);}
if (xon)
{xPos = xPos + step;}
else
{xPos = xPos - step;}
if (xPos < 0)
{xon = 1;xPos = 0;}
if (xPos >= (width - Woffset))
{xon = 0;xPos = (width - Woffset); }
}
function start()
{
img1.visibility = "visible";
interval = setInterval('changePos()', delay);
//interval = setTimeout("changePos()", delay);
}
function pause_resume()
{
if(pause)
{
clearInterval(interval);
pause = false;}
else
{
interval = setInterval('changePos()',delay);
pause = true;
}
}
start();




JS实现气泡从水中急速上升效果
代码如下:





var object = new Array();
nbfm = 60;
var xm = 0;
var ym = 9999;
var nx = 0;
var ny = 0;
function movbulb(){
with (this) {
if(ec < 20){
if(Math.abs(x0 - xm) < 100 && Math.abs(y0 - ym) < 100){
xx = (xm - x0) / 8;
yy = (ym - y0) / 8;
ec++;
}
}
xx *= 0.99;
yy *= 0.99;
x0 = Math.round(x0 + Math.cos(y0 / 15) * p) + xx;
y0+= yy - v;
if(y0 < -h * 2 || x0 < -w * 2 || x0 > nx + w * 2){
y0 = ny + N + h * 2;
x0 = nx/2-100 + Math.random() * 100;
ec = 0;
}
obj.style.top = y0 - h;
obj.style.left = x0 - w;
}
}
function CObj(N,img,w,h){
this.obj = document.createElement("img");
this.obj.src = img.src;
this.obj.style.position = "absolute";
this.obj.style.left = -1000;
document.body.appendChild(this.obj);
this.N = N;
this.x0 = 0;
this.y0 = -1000;
this.v = 1 + Math.round((80 / h) * Math.random());
this.p = 1 + Math.round((w / 8) * Math.random());
this.xx = 0;
this.yy = 0;
this.ec = 0;
this.w = w;
this.h = h;
this.movbulb = movbulb;
}
function resize(){
nx = document.body.offsetWidth;
ny = document.body.offsetHeight;
}
onresize = resize;
document.onmousemove = function(e){
if (window.event) e = window.event;
xm = document.body.scrollLeft+(e.x || e.clientX);
ym = document.body.scrollTop+(e.y || e.clientY);
}
function run(){
for(i in object)object[i].movbulb();
setTimeout(run, 16);
}
onload = function() {
PIC = document.getElementById("bubbles").getElementsByTagName("img");
resize();
for(nbf=0;nbf sf = PIC[nbf%PIC.length];
object[nbf] = new CObj(nbf,sf,sf.width/2,sf.height/2);
}
run();
}












浮动广告
代码如下:













var x = 400,y = 300
var xin = true, yin = true
var step = 1
var delay = 25
var obj=document.getElementById("ad")
function floatAD()
{
var L=T=0
var R= document.body.clientWidth-obj.offsetWidth
var B = document.body.clientHeight-obj.offsetHeight
obj.style.left = x + document.body.scrollLeft
obj.style.top = y + document.body.scrollTop
x = x + step*(xin?1:-1)
if (x < L) { xin = true; x = L}
if (x > R){ xin = false; x = R}
y = y + step*(yin?1:-1)
if (y < T) { yin = true; y = T }
if (y > B) { yin = false; y = B }
}
var itl= setInterval("floatAD()", delay)
function closeWindow()
{
window.close();
}