CSS3的transform: scale()可以按比例放大或缩小block的功能。
源码如下
<!DOCTYPE html><html>
<head>
<meta charset="UTF-8">
<title>CSS3鼠标滑过图片放大特效DEMO演示</title>
<style>
html{font-family:sans-serif-ms-text-size-adjust:100%-webkit-text-size-adjust:100%}body{margin:0}article,aside,details,figcaption,figure,footer,header,hgroup,main,nav,section,summary{display:block}audio,canvas,progress,video{display:inline-blockvertical-align:baseline}audio:not([controls]){display:noneheight:0}[hidden],template{display:none}a{background:transparent}a:active,a:hover{outline:0}abbr[title]{border-bottom:1px dotted}b,strong{font-weight:bold}dfn{font-style:italic}h1{font-size:2emmargin:0.67em 0}mark{background:#ff0color:#000}small{font-size:80%}sub,sup{font-size:75%line-height:0position:relativevertical-align:baseline}sup{top:-0.5em}sub{bottom:-0.25em}img{border:0}svg:not(:root){overflow:hidden}figure{margin:1em 40px}hr{-moz-box-sizing:content-boxbox-sizing:content-boxheight:0}pre{overflow:auto}code,kbd,pre,samp{font-family:monospace, monospacefont-size:1em}button,input,optgroup,select,textarea{color:inheritfont:inheritmargin:0}button{overflow:visible}button,select{text-transform:none}button,html input[type="button"],input[type="reset"],input[type="submit"]{-webkit-appearance:buttoncursor:pointer}button[disabled],html input[disabled]{cursor:default}button::-moz-focus-inner,input::-moz-focus-inner{border:0padding:0}input{line-height:normal}input[type="checkbox"],input[type="radio"]{-moz-box-sizing:border-boxbox-sizing:border-boxpadding:0}input[type="number"]::-webkit-inner-spin-button,input[type="number"]::-webkit-outer-spin-button{height:auto}input[type="search"]{-webkit-appearance:textfield-moz-box-sizing:content-boxbox-sizing:content-box}input[type="search"]::-webkit-search-cancel-button,input[type="search"]::-webkit-search-decoration{-webkit-appearance:none}fieldset{border:1px solid #c0c0c0margin:0 2pxpadding:0.35em 0.625em 0.75em}legend{border:0padding:0}textarea{overflow:auto}optgroup{font-weight:bold}table{border-collapse:collapseborder-spacing:0}td,th{padding:0}
</style>
<style>
@import url("http://fonts.googleapis.com/css?family=Lato")
* {
margin: 0
padding: 0
box-sizing: border-box
}
body {
font: 14px/1 Lato, sans-serif
color: #555
background: #eee
}
.gallery {
width: 790px
margin: 30px auto
padding: 5px
background: #333
}
.gallery > div {
position: relative
float: left
padding: 5px
}
.gallery > div > img {
width: 250px
transition: .1s transform
transform: translateZ(0)
/* hack */
}
.gallery > div:hover {
z-index: 1
}
.gallery > div:hover > img {
transform: scale(1.5, 1.5)
transition: .3s transform
}
.cf:before, .cf:after {
display: table
content: ""
line-height: 0
}
.cf:after {
clear: both
}
h1 {
margin: 40px 0
font-size: 24px
text-align: center
text-transform: uppercase
}
footer {
margin: 80px 0
text-align: center
}
</style>
<script src="js/prefixfree.min.js"></script>
</head>
<body>
<div class="gallery cf">
<div>
<img src="landscape-test-1_1x.jpg" />
</div>
<div>
<img src="iceberg_1x.jpg" />
</div>
<div>
<img src="igloo-800_1x.jpg" />
</div>
<div>
<img src="trees_1x.jpg" />
</div>
<div>
<img src="space_1x.jpg" />
</div>
<div>
<img src="render1_1x.jpg" />
</div>
</div>
<div style="text-align:centerclear:both">
<script src="/gg_bd_ad_720x90.js" type="text/javascript"></script>
<script src="/follow.js" type="text/javascript"></script>
</div>
</body>
</html>
img:hover{}设置宽高属性，比默认情况大就行。注意与周围元素的协调，避免放大后布局错乱。不过这类行为范畴的东西最好交由JS来完成。
还有就是IE6对元素伪类支持不好，hover有bug。测试的时候要注意。
