JS按比例缩放图片

//来自：新浪网-新闻中心(http://news.sina.com.cn/)
//调用：<img src="" onload="javascript:DrawImage(this)">
function DrawImage(ImgD){
	var image=new Image();
	var iwidth = 120; //默认宽
	var iheight = 120; //默认高
	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;
			}
		}else{
			if(image.height>iheight){ 
				ImgD.height=iheight;
				ImgD.width=(image.width*iheight)/image.height; 
			}else{
				ImgD.width=image.width; 
				ImgD.height=image.height;
			}
		}
	}
} 

//来自：QZone(http://270250392.qzone.qq.com/)
function adjustSize(obj,w,h,openWindows){
	obj.onload=null;
	if(w<=0||h<=0)return ;
	var w0=obj.width,h0=obj.height,r=false;
	if(w0<1){
		var i=new Image();
		i.src=obj.src;
		w0=i.width;
		h0=i.height;
	}
	if((w0/h0)>(w/h)){
		if(w0>w){
			setTimeout(function (o,i){	return function(){o.style.width=i}}(obj,w),0);
			w0=w;
			r=true;
		}
	}else {
		if(h0>h){
			setTimeout(function (o,i){return function (){o.style.height=i}}(obj,h),0);
			h0=h;
			r=true;
		}
	}
	if(openWindows&&r){
		obj.style.cursor="pointer";
		obj.title="点击预览原图";
		obj.onclick=function (){window.open(obj.src);}
	}
	if(!!obj.transImg&&Browser.isIE&&!Browser.isIE7){
		obj.style.filter="progid:DXImageTransform.Microsoft.AlphaImageLoader(enabled=true,src="+obj.src+",sizingmethod=scale);";
		obj.style.height=h0;
		obj.style.width=w0;
		obj.src="/ac/qzone_v4/b.gif";
	}
}