每天一个JS 小demo之滑屏幻灯片。主要知识点：event

document

body {
margin: 0;
}
#wrap {
margin: 100px auto;
position: relative;
width: 400px;
height: 300px;
border: 5px solid #000;
overflow: hidden;
}
#list {
position: absolute;
left: 0;
top: 0;
width: 400%;
list-style: none;
padding: 0;
margin: 0;
}
#list li {
width: 25%;
float: left;
}
img {
vertical-align: top;
}
#navs {
position: absolute;
left: 0;
bottom: 30px;
height: 12px;
width: 100%;
text-align: center;
}
#navs a {
display: inline-block;
width: 12px;
height: 12px;
vertical-align: top;
background: #fff;
margin: 0 5px;
border-radius: 6px;
}
#navs .active {
background: #f60;
}