js 实现当前元素是否是指定元素的子集

function ifParentObj(obj,parentObj){
   while (obj != undefined && obj != null && obj.tagName.toUpperCase() != 'BODY'){ 
      if (obj == parentObj){ 
      return true; 
      } 
      obj = obj.parentNode; 
          } 
    return false; 
}

demo :点击非菜单触发按钮及菜单区域隐藏菜单

• html

<div class="nav-bar bg-grey main-body" @click="hideDropList($event)">
 <div id="dropBody" slot-scope="_" :width="30" class="relative">
                    <i class="fa fa-caret-down fa-2x" @click="showDropList"></i>
                    <drop-down                     
                      class="drop-list-body"
                      :dropList="dropList"
                      :listData="listData"
                    ></drop-down>
                  </div>
</div>

• js

 hideDropList(e) {
      let evt = e.srcElement ? e.srcElement : e.target;
      let parentO=document.getElementById("dropBody");
        // if  itself and it's children then do nothing,else hide 
      if (evt.id == "dropBody"||this.isParentObj(evt,parentO)) return;    
      else {
        this.dropList = false; 
      }
    }