CSS控制图片的最大宽度

<img class="photoresize" style="border:1px solid #ccc; padding:2px; margin:10px;" src="<%=rs("img")%>" />

<style type="text/css">
          .photoresize {
 max-width:600px;
 myimg:expression(onload=function(){
 this.style.width=(this.offsetWidth > 600)?"600px":"auto"}
     );
 }
          </style>

.neirong img{max-width:680px;myimg:expression(onload=function(){this.style.width=(this.offsetWidth > 680)?"680px":"auto"});}
#upscroll li{ height:20px; line-height:20px;}