code: function findParentByTagName(target, tagNames) {
              var i, current = target;
              tagNames = utils.isArray(tagNames) ? tagNames:[tagNames];
              while(current){
                  for(i = 0;i < tagNames.length; i++) {
                      if(current.tagName == tagNames[i].toUpperCase()) return current;
                  }
                  current = current.parentNode;
              }
              return null;
          }
docs: 按照标签名查找父节点