用Javascript将图片等比例缩放

并非原创，主要是产品部的需求。对网站商户图片进行等比例缩放。

script：
function resizeimg(ImgD,iwidth,iheight) {
     var image=new Image();
     image.src=ImgD.src;
     if(image.width>0 && image.height>0){
        if(image.width/image.height>= iwidth/iheight){
           if(image.width>iwidth){
               ImgD.width=iwidth;
               ImgD.height=(image.height*iwidth)/image.width;
           }else{
                  ImgD.width=image.width;
                  ImgD.height=image.height;
                }
               ImgD.alt=image.width+"×"+image.height;
        }
        else{
                if(image.height>iheight){
                       ImgD.height=iheight;
                       ImgD.width=(image.width*iheight)/image.height;
                }else{
                        ImgD.width=image.width;
                        ImgD.height=image.height;
                     }
                ImgD.alt=image.width+"×"+image.height;
            }
ImgD.style.cursor= "pointer"; //改变鼠标指针
ImgD.onclick = function() { window.open(this.src);} //点击打开大图片
if (navigator.userAgent.toLowerCase().indexOf("ie") > -1) { //判断浏览器，如果是IE
ImgD.title = "请使用鼠标滚轮缩放图片，点击图片可在新窗口打开";
ImgD.onmousewheel = function img_zoom() //滚轮缩放
 {
var zoom = parseInt(this.style.zoom, 10) || 100;
zoom += event.wheelDelta / 12;
if (zoom> 0)　this.style.zoom = zoom + "%";
return false;
 }
  } else { //如果不是IE
     ImgD.title = "点击图片可在新窗口打开";
   }
    }
}
HTML:
<img id="imgDoc" border="0" src="test.jpg" onload="javascript:resizeimg(this,400,300);" >

 

引用：http://www.rev9.cn/article.asp?id=82

Google 标记: Javascript, 等比例缩放