#slideshow{width:100px;height:100px;position:relative; overflow:hidden;}<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Web Design</title>
<script src="addLoadEvent.js"></script>
<link rel="stylesheet" type="text/css" href="10.2.css" >
<script src="10.2.js"></script>
</head>
<body>
<h2>Web Design</h2>
<p>These are the things you should know.</p>
<ol id="linklist">
<li><a href="structure.html">Structure</a></li>
<li><a href="presentation.html">Presentation</a></li>
<li><a href="behavior.html">Behavior</a></li>
</ol>
<div id="slideshow">
<img src="topics.gif" alt="building bolcks of web design" id="preview" />
</div>
</body>
</html>
function addLoadEvent(func){ //不管在页面加载完毕执行多少个函数，都应付自如
var oldonload = window.onload;
if(typeof window.onload != 'function'){
window.onload = func;
}else{
window.onload = function(){
oldonload();
func();
}
}
}
//加快速度，距离越远，速度越快，距离越近，速度越慢
function moveElement(elementID,final_x,final_y,interval){
if(!document.getElementById) return false;
if(!document.getElementById(elementID)) return false;
var elem = document.getElementById(elementID);
if(elem.movement){
clearTimeout(elem.movement); //进行复位
}
var xpos = parseInt(elem.style.left); //parseInt(string)把字符串里面的数值信息提取出来，因为后面要进行很多算术比较操作。
var ypos = parseInt(elem.style.top); //parseFloat(string)可以把带小数的数值（也就是浮点数）提取出来。
var dist = 0;
if(xpos == final_x && ypos == final_y){
return true;
}
if(xpos < final_x){
dist = Math.ceil(( final_x - xpos)/10); //Math.ceil是向上取整函数，它返回的是大于或等于函数参数，并且与之最接近的整数，防止移动距离小于1像素.
xpos = xpos + dist;
}
if(xpos > final_x){
dist = Math.ceil(( xpos - final_x)/10);
xpos = xpos - dist;
}
if(ypos < final_y){
dist = Math.ceil(( final_y - ypos)/10);
ypos = ypos + dist;
}
if(ypos > final_y){
dist = Math.ceil(( ypos - final_y)/10);
ypos = ypos - dist;
}
elem.style.left = xpos + "px";
elem.style.top = ypos + "px";
//var repeat = function() {moveElement(elementID, final_x,final_y,interval)}
var repeat = "moveElement('" + elementID + "'," + final_x + "," + final_y + "," + interval + ")";
elem.movement = setTimeout(repeat,interval); //为元素创建属性movement，element.property = value;
}
function prepareSlideshow(){
//确保浏览器支持DOM方法。
if(!document.getElementsByTagName) return false;
if(!document.getElementById) return false;
//确保元素存在。
if(!document.getElementById("linklist")) return false;
if(!document.getElementById("preview")) return false;
//为图片应用样式。
var preview = document.getElementById("preview");
preview.style.position = "absolute";
preview.style.left = "0px";
preview.style.top = "0px";
//取得列表中所有链接。
var list = document.getElementById("linklist");
var links = list.getElementsByTagName("a");
//为mouseover事件添加动画效果。
links[0].onmouseover = function(){
moveElement("preview",-100,0,10);
}
links[1].onmouseover = function(){
moveElement("preview",-200,0,10);
}
links[2].onmouseover = function(){
moveElement("preview",-300,0,10);
}
}
addLoadEvent(prepareSlideshow);图片素材：
浏览器效果：
