CSS控制DIV里图片的宽度固定 而高度自动缩放比例

function imgSize(url ,id) {

var imgObj = new Image();

var imgDiv=document.getElementById(id)

imgObj.src = url;

imgDiv.innerHTML= imgObj.width + " × " + imgObj.height;

}

function changeSize(obj, width) {

if (obj.width > width) {

obj.width=width;

}

}

</SCRIPT>

<style type="text/css">

body {

font-size: 12px;

text-align: center;

margin: 0px;

padding: 0px;

}

.picimg{

margin:10 auto;

padding:0;

background:#F93;

 border-bottom:1px #33C solid;

 overflow:hidden; width:300px

}

.picimg img{

myimg:expression(

onload=changeSize(this, 1)

);

}

</style>

<div style="width:100px" class="picimg">

<img src="http://www.veryhuo.com/uploads/common/images/liehuo_1024x768_1.jpg" border="0"  style="width:100px" onl oad="changesize(this, 1);">

</div><br />

<div style="width:200px" class="picimg">

<img src="http://www.veryhuo.com/uploads/common/images/liehuo_1024x768_1.jpg" border="0"  style="width:200px" onl oad="changesize(this, 1);">

</div><br />

<div style="width:300px" class="picimg">

<img src="http://www.veryhuo.com/uploads/common/images/liehuo_1024x768_1.jpg" border="0"  style="width:300px" onl oad="changesize(this, 1);">

</div><br />

<div style="width:400px" class="picimg">

<img src="http://www.veryhuo.com/uploads/common/images/liehuo_1024x768_1.jpg" border="0"  style="width:400px" onl oad="changesize(this, 1);">

</div><br />