function swap(targetId,buttonId){
  
  if (document.getElementById)
        {
        target = document.getElementById(targetId);
  	    buttonName = document.getElementById(buttonId);
          
            if (target.style.display == "none")
                {
                target.style.display = "block";
                } 
            else 
                {
                target.style.display = "none";
                }

			if (target.style.display == "none")
                {
                buttonName.src = "assets/closed.gif";
                }
            else 
                {
                buttonName.src = "assets/open.gif";
                }
                
        }
}