JS控制图片等比例缩放的示例代码

<SCRIPT language="JavaScript">
function DrawImage(ImgD,FitWidth,FitHeight){   
    var image=new Image();   
    image.src=ImgD.src;   
    if(image.width>0 && image.height>0){   
        if(image.width/image.height>= FitWidth/FitHeight){   
            if(image.width>FitWidth){   
                ImgD.width=FitWidth;   
                ImgD.height=(image.height*FitWidth)/image.width;   
            }   
            else{   
                ImgD.width=image.width;   
                ImgD.height=image.height;   
            }   
        }   
        else{   
            if(image.height>FitHeight){   
                ImgD.height=FitHeight;   
                ImgD.width=(image.width*FitHeight)/image.height;   
            }   
            else{   
                ImgD.width=image.width;   
                ImgD.height=image.height;   
            }   
        }   
    }   
}   
</script>

调用方法：

<a href="admin/<? echo $rscase['path']?>" target="_blank"><img src="admin/<? echo $rscase['path']?>" alt="点击放大图片" width="180" height="180" onload='javascript:DrawImage(this,180,);' hspace="3" vspace="3" border="0" /></a>