JS对图片缩放处理

        function DrawImage(ImgD, iwidth, iheight) {
            //参数(图片,允许的宽度,允许的高度)
            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;
                }
            }
        } 

页面内调用：  <img src="Images/03.jpg" onload="javascript:DrawImage(this,100,100)">

这个方法是从网上找的，实践可用，并已经用在项目中，简单方便。可读性强