通过JS，按照原比例控制图片尺寸
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>Js压缩图片</title>
<script type="text/javascript" >
//img：图片对象
// w：宽度
// h：高度
function ctlImg(img, w, h) {
var img_Width = w;
var img_Height = h;
var w = img.width;
var h = img.height;
if (img.width > img_Width && img.height > img_Height) {
if (w / img_Width > h / img_Height) {
img.width = img_Width;
img.height = parseInt(img_Width / w * h);
}
else {
img.height = img_Height;
img.width = parseInt(img_Height / h * w);
}
return true;
}
if (w > img_Width) {
img.width = img_Width;
img.height = parseInt(img_Width * (h / w));
} else if (h > img_Height) {
img.height = img_Height;
img.width = parseInt(img_Height * (w / h));
}
return true;
}
</script>
</head>
<body >
<img alt="" src="1.jpg " onload="ctlImg(this,80,60)"/>
<img alt="" src="2.jpg " onload="ctlImg(this,800000,600)"/>
<img alt="" src="3.jpg " onload="ctlImg(this,80,60)"/>
<img alt="" src="4.jpg " onload="ctlImg(this,8000,100)"/>
</body>
</html>
