function showhide(obj)
{
var objct = document.getElementById(obj);
 if(objct.style.visibility =='visible')
 {
  objct.style.visibility ='hidden';
  objct.style.position   ='absolute';
 }
 else if(objct.style.visibility =='hidden')
 {
  objct.style.visibility ='visible';
  objct.style.position   ='relative';
 }

}