// JavaScript Document
//图片按比例缩放

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){//比例相同
				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;
			}
    }
}