/**
 * Created by tgy on 2018/1/3.
 */
window.onload = function () {


  var shortcut = document.getElementsByClassName("nav-lef")[0];
  var top = shortcut.getElementsByClassName("top")[0];
  var down = shortcut.getElementsByClassName("down")[0];
  // shortcut.onmouseover
  shortcut.addEventListener('mouseover',function () {

      show(down);
  })

  // shortcut.onmouseout
  shortcut.addEventListener("mouseout", function () {
    hide(down);
    // this.style.borderBottomColor = "#000";
  })

}


function show(el) {

    el.className =  el.className.replace("hide","show");
}

function hide(el) {

  el.className = el.className.replace("show","hide");
}