HTML 标记

Created: November-22, 2018

示例输入：

<html>
  <head>
    <title>the title</title>
    <link href='css/app.css' type='text/css' rel='stylesheet'>
    <script src='js/app.js'></script>
  </head>
  <body>
    <h1>header</h1>
    <div>
      <p>hello!</p>
    </div>
  </body>
</html>

DOM 元素输出：

                             ------------                             
                             | document |    <--- DOM root object.                           
                             ------------                             
                                  |                                   
                                  |                                   
                             ------------                             
                             |   html   |     <--- document.documentElement                  
                             ------------                             
                    ______________|______________                     
                    |                           |                     
               ------------                ------------               
               |   head   |                |   body   |               
               ------------                ------------               
      ______________|______________             |______________       
      |             |             |             |             |       
 ------------  ------------  ------------  ------------  ------------ 
 |  title   |  |   link   |  |  script  |  |    h1    |  |   div    | 
 ------------  ------------  ------------  ------------  ------------ 
                                                              |       
                                                              |       
                                                         ------------ 
                                                         |    p     | 
                                                         ------------

以上所有元素都继承自 HTMLElement 接口，并根据特定标记进行自定义