IE浏览器移除下拉选按钮的方法！
- https://codepen.io/vkjgr/pen/VYMeXp；
- https://codepen.io/jackocnr/pen/lmAeh；
- http://m.blog.csdn.net/article/details?id=42268329；
- http://stackoverflow.com/questions/19407332/how-to-hide-drop-down-arrow-in-ie8-ie9；
- https://harvesthq.github.io/chosen/；
- http://stackoverflow.com/questions/20163079/remove-select-arrow-on-ie；
