百度源代码里的精妙javascript图片大小处理函数

<script language=Javascript>

var proMaxHeight = 150;

var proMaxWidth = 110;

function proDownImage(ImgD){

var image=new Image();

image.src=ImgD.src;

if(image.width>0 && image.height>0){

var rate = (proMaxWidth/image.width < proMaxHeight/image.height)?proMaxWidth/image.width:proMaxHeight/image.height;

if(rate <= 1){

ImgD.width = image.width*rate;

ImgD.height =image.height*rate;

}

else {

ImgD.width = image.width;

ImgD.height =image.height;

}

}

}

</script>

<img src="http://www.baidu.com/images/logo.gif" onload=proDownImage(this); />