droplist

  //初始化dom结构   
  function initDom(options){
   $dom = self.$dom = $("<div class='combox'></div>").appendTo($container);
   self.$inputbox = $("<input type='text' class='inputbox'/>").appendTo($dom);
   $(document).bind("click",blurFn);
   self.$inputbox.attr("readonly",!settings.inputEnable);
   $trigger=$("<span class='trigger'></span>").appendTo($dom).click(clickFn); 
  
   //下拉列表
   $list = self.$listdom = $("<div class='popdiv'></div>").appendTo($container);
   var maxZ = getMaxZIndex();
   $list.css("z-index",maxZ+1);
   
   $.each(settings.data,function(index){
    var item = createSelectItem(this,index);
    items.push(item);
   });
  }