输出结果如下：

{ [Function: initialize]

  fn:

   initialize {

     constructor: [Circular],

     _originalRoot:

      { type: 'root',

        name: 'root',

        namespace: 'http://www.w3.org/1999/xhtml',

        attribs: {},

        'x-attribsNamespace': {},

        'x-attribsPrefix': {},

        children: [Array],

        parent: null,

        prev: null,

        next: null } },

  load: [Function],

  html: [Function],

  xml: [Function],

  text: [Function],

  parseHTML: [Function],

  root: [Function],

  contains: [Function],

  merge: [Function],

  _root:

   { type: 'root',

     name: 'root',

     namespace: 'http://www.w3.org/1999/xhtml',

     attribs: {},

     'x-attribsNamespace': {},

     'x-attribsPrefix': {},

     children: [ [Object], [Object] ],

     parent: null,

     prev: null,

     next: null },

  _options:

   { decodeEntities: false,

     withDomLvl1: true,

     normalizeWhitespace: false,

     xml: false } }

啥信息都没有。

但是输出html却能输出网页的内容