【jquery、XML】jquery通过按钮使打开select

 <select>
     <option>aaaaa</option>
     <option>bbbbb</option>
     <option>ccccc</option>
 </select>
 <button>button</button>
 <script>
     $.fn.openSelect = function() {
         return this.each(function(idx,domEl) {
             if (document.createEvent) {
                 var event = document.createEvent("MouseEvents");
                 event.initMouseEvent("mousedown", true, true, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
                 domEl.dispatchEvent(event);
             } else if (element.fireEvent) {
                 domEl.fireEvent("onmousedown");
             }
         });
     }
     $('button').on('click', function() {
         $('select').openSelect();
     });
 </script>

该处用到了XML的【XML】document.createEvent的使用方法