// JavaScript Document
  function   DrawImage(ImgD,wth,hth){   
        var   image=new   Image();   
        var   iwidth   =   wth;     //定义允许图片宽度   
        var   iheight   =   hth;     //定义允许图片高度   
        image.src=ImgD.src;   
        if(image.width>0   &&   image.height>0){   
          flag=true;   
          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;   
            }   
           //ImgD.alt="点击放大("+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="点击放大("+image.width+"×"+image.height+")";   
            }   
          }   
  }