$(document).ready(function () {
  $(".btn img").hover(function () {
    $(this).attr("src", "images/" + $(this).attr("name") + " hover.jpg");
  }, function () {
    $(this).attr("src", "images/" + $(this).attr("name") + ".jpg");
  });

  var f = false;
  $("#tradeshowbooths").mouseenter(function () {
    f = true;
    $(".submenu").slideDown("fast").mouseenter(function () {
      f = false;
    }).mouseleave(function () {
      f = false;
      $(this).slideUp("fast");
    });
  }).mouseleave(function () {
    setTimeout(function () {
      if (f) {
        f = false;
        $(".submenu").slideUp("fast");
      }
    }, 100);
  });
});