code: function (node, tagName, attrs) {
          var list = domUtils.getElementsByTagName(node, node.tagName.toLowerCase());
          for (var i = 0, ci; ci = list[i++];) {
              if (!ci.parentNode || domUtils.isBookmarkNode(ci)) {
                  continue;
              }
              //span单独处理
              if (ci.tagName.toLowerCase() == 'span') {
                  if (node === ci.parentNode) {
                      domUtils.trimWhiteTextNode(node);
                      if (node.childNodes.length == 1) {
                          node.style.cssText = ci.style.cssText + ";" + node.style.cssText;
                          domUtils.remove(ci, true);
                          continue;
                      }
                  }
                  ci.style.cssText = node.style.cssText + ';' + ci.style.cssText;
                  if (attrs) {
                      var style = attrs.style;
                      if (style) {
                          style = style.split(';');
                          for (var j = 0, s; s = style[j++];) {
                              ci.style[utils.cssStyleToDomStyle(s.split(':')[0])] = s.split(':')[1];
                          }
                      }
                  }
                  if (domUtils.isSameStyle(ci, node)) {
                      domUtils.remove(ci, true);
                  }
                  continue;
              }
              if (domUtils.isSameElement(node, ci)) {
                  domUtils.remove(ci, true);
              }
          }
      }
docs: 合并node节点下相同的子节点
  @name mergeChild
  @desc
  UE.dom.domUtils.mergeChild(node,tagName) //tagName要合并的子节点的标签
  @example
  <p><span style="font-size:12px;">xx<span style="font-size:12px;">aa</span>xx</span></p>
  ==> UE.dom.domUtils.mergeChild(node,'span')
  <p><span style="font-size:12px;">xxaaxx</span></p>