function showSubmenu() {
  document.getElementById("submenu").style.display="block";
}
function hideSubmenu() {
  document.getElementById("submenu").style.display="none";
}
function highlightItem(num) {
  if (num==1) {
    document.getElementById("r1c2").style.backgroundColor="rgb(230,230,230)";
  }
  if (num==2) {
    document.getElementById("r2c2").style.backgroundColor="rgb(230,230,230)";
  } 
}
function revertItem(num) {
  if (num==1) {
    document.getElementById("r1c2").style.backgroundColor="rgb(240,240,240)";
  }
  if (num==2) {
    document.getElementById("r2c2").style.backgroundColor="rgb(240,240,240)";
  } 
}
function goto(num) {
  if (num==1) {
    location.href="boats.php";
  }
  if (num==2) {
    location.href="jetskis.php";
  }
}