code: function (element) {
      var currentNode = element.parentNode
      while (currentNode) {
        if (currentNode.tagName === 'HTML') {
          return true
        }
        if (currentNode.nodeType === 11) {
          return false
        }
        currentNode = currentNode.parentNode
      }
      return false
    }
docs: 判断该元素是否已经加入dom树
  @param element
  @returns {boolean}