function Menu(dat)
{

for(i=1; i<=5; i++)
{
if(i==dat){
if(document.getElementById("M"+i).style.display == "") document.getElementById("M"+i).style.display = "none";
else document.getElementById("M"+i).style.display = "";
}
else	        document.getElementById("M"+i).style.display = "none";
  }
}