长度跟宽度自动缩放

高度自动
height:expression(document.180.clientWidth < 180? "180px": "auto" );

宽度限制
?class="imgzoom"
.imgzoom img {behavior: url("${base}/styles/imgzoom.htc");
<script language="javascript">
? var _width = element.width;
? var _hieght = element.height;
? var _maxpixel = _width;
? var _which = "w";
? var maxwidth = 680;
? var maxheight = 680;
?
? //element.onmousewheel = test;
? if (element.width > maxwidth) {
??? element.width = maxwidth;
??? element.removeAttribute("height");
???
??? if (element.parentElement.tagName != "A"){???
????? var _html = "";
????? _html += "<a href=\""+element.src+"\" target=\"_blank\">";
????? _html += element.outerHTML;
????? _html += "</a>";
????? element.outerHTML = _html;
??? }
? }
? /*
? if (height > _width) {
??? _maxpixel = _hieght;
??? _which = "h";
? }
? if (_which == "w") {
??? if (element.width > maxwidth) {
????? element.width = maxwidth;
????? element.removeAttribute("height");
??? }
? }
? else {
??? if (element.height > maxheight) {
????? element.height = maxheight;
????? element.removeAttribute("width");
??? }
? }*/

? function test() {
??? return zoomimg(element)
? }

function zoomimg(pic){
? var zoom=parseInt(pic.style.zoom,10)||100;
? zoom+=event.wheelDelta/12;
? if (zoom>0) pic.style.zoom=zoom+'%';
? return false;
}
</script>