<!--
current_img="";

function img_on(img,src)
  {
  img_off()
  eval("current_src=document."+img+".src");
  eval("document."+img+".src='"+src+"'");
  current_img=img;  
  }

function img_off()
  {
  if (current_img!="")
     { eval("document."+current_img+".src=current_src"); current_img="";  }
  }
// -->