function showMenuItem(element){
  if(element.className == "mainmenu"){
    element.className = "mainmenu hover";
  }
  else if(element.className == "submenu"){
    element.className = "submenu hover";
  }
  else{
    element.className = "hover";
  }
}
function hideMenuItem(element){
  if(element.className == "mainmenu hover"){
    element.className = "mainmenu";
  }
  else if(element.className == "submenu hover"){
    element.className = "submenu";
  }
  else{
    element.className = "";
  }
}