if (mtDropDown.isSupported()) {
  var ms = new mtDropDownSet(mtDropDown.direction.down, 0, 0, mtDropDown.reference.bottomLeft);
  var menu1 = ms.addMenu(document.getElementById("menu1"));
  menu1.addItem(" 公司简介 ", "classinfo.aspx?classid=40");
  menu1.addItem(" 生产设备 ", "pic.aspx?classid=41");
  menu1.addItem(" 厂容厂貎 ", "pic.aspx?classid=42");

  var menu2 = ms.addMenu(document.getElementById("menu2"));
  menu2.addItem(" 单向透视膜 ", "products.aspx?classid=6&id=182");
  menu2.addItem(" 透明窗贴 ", "products.aspx?classid=6&id=186");
  menu2.addItem(" 车 身 贴 ", "products.aspx?classid=6&id=184");
  menu2.addItem(" 热升华旗帜布 ", "products.aspx?classid=6&id=187");
  menu2.addItem(" 其他产品 ", "products.aspx?classid=6&id=188");

  var menu3 = ms.addMenu(document.getElementById("menu3"));
  menu3.addItem(" 玻璃幕墙 ", "pic.aspx?classid=46");
  menu3.addItem(" 车窗玻璃 ", "pic.aspx?classid=47");
  menu3.addItem(" 地  铁 ", "pic.aspx?classid=48");
  menu3.addItem(" 橱  窗 ", "pic.aspx?classid=49");

  var menu4 = ms.addMenu(document.getElementById("menu4"));
  menu4.addItem(" 企业动态 ", "news.aspx?classid=26");
  menu4.addItem(" 行业资讯 ", "news.aspx?classid=27");
  menu4.addItem(" 最新公告 ", "news.aspx?classid=32");

  mtDropDown.renderAll();
 }