function showSkypeBox() {
  var skypebox = document.getElementById("skypebox");
  skypebox.style.left = (mouse_x + 30) + "px";
  skypebox.style.top = (mouse_y - 30) + "px";
  skypebox.style.visibility = "visible";
}
function hideSkypeBox() {
  var skypebox = document.getElementById("skypebox");
  skypebox.style.visibility = "hidden";
}