function ShowFirst()
    {
       document.getElementById("DMItem").style.visibility = "visible";
       document.getElementById("DMItem").style.display = "block";
       
       document.getElementById("DAItem").style.visibility = "hidden";
       document.getElementById("DAItem").style.display = "none";
       
       document.getElementById("DLItem").style.visibility = "hidden";
       document.getElementById("DLItem").style.display = "none";
    }
    
    function ShowNext()
    {
       document.getElementById("DMItem").style.display = "none";
       document.getElementById("DMItem").style.visibility = "hidden";
       
       document.getElementById("DAItem").style.visibility = "visible";
       document.getElementById("DAItem").style.display = "block";             
       
       document.getElementById("DLItem").style.visibility = "hidden";
       document.getElementById("DLItem").style.display = "none";
    }          
      
    function ShowLast()
    {
       document.getElementById("DMItem").style.display = "none";
       document.getElementById("DMItem").style.visibility = "hidden";

       document.getElementById("DAItem").style.visibility = "hidden";
       document.getElementById("DAItem").style.display = "none";
              
       document.getElementById("DLItem").style.visibility = "visible";
       document.getElementById("DLItem").style.display = "block";
    }