title: Property 'querySelector' does not exist on type 'Node'. in TypeScript
body: <p>I have the following code:
  test.html</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
  &lt;head lang="zh-CN"&gt;
      &lt;meta charset="UTF-8"&gt;
      &lt;meta name="viewport" content="width=device-width, initial-scale=1"/&gt;
      &lt;title&gt;&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;div id="container"&gt;
          &lt;div id="box"&gt;&lt;/div&gt;
      &lt;/div&gt;
      &lt;script src="test.js"&gt;&lt;/script&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>and the ts file test.ts</p>
  
  <pre><code>var box = document.querySelector('#box');
  console.log(box.parentNode.querySelector('#box'));
  </code></pre>
  
  <p>and i got the error.</p>
  
  <pre><code>Error:(2, 28) TS2339: Property 'querySelector' does not exist on type 'Node'.
  </code></pre>
  
  <p>I found the following sentence in <a href="https://developer.mozilla.org/en-US/docs/Web/API/Node/parentNode" rel="noreferrer">MDN</a></p>
  
  <p><strong>parentNode is the parent of the current node. The parent of an element is an Element node, a Document node, or a DocumentFragment node.</strong></p>
  
  <p>here is my test</p>
  
  <pre><code>var ul = document.querySelector('ul')
  undefined
  ul.parentNode.toString()
  [object HTMLDivElement]"
  </code></pre>
  
  <p>could someone tell me what's wrong with that?</p>
  
  <p>the version of typescript is 1.4</p>