title: Elegant way to include es6-promise for IE
body: <p>Since <code>Promise</code> is <a href="http://caniuse.com/#search=promise" rel="nofollow noreferrer">not support</a> in all IE versions, I would like to make the IE users to download a pollyfill in HTML.</p>
  
  <pre><code>&lt;!--[if IE]&gt;
  &lt;script src="//cdnjs.cloudflare.com/ajax/libs/es6-promise/4.1.1/es6-promise.min.js"&gt;&lt;/script&gt;
  &lt;![endif]--&gt;
  </code></pre>
  
  <p>However, <a href="https://msdn.microsoft.com/en-us/library/hh801214(v=vs.85).aspx" rel="nofollow noreferrer">conditional comments are not supported</a> in IE 10 and 11. So the above code doesn't work in IE 10 and 11.</p>
  
  <p>Then, Microsoft provide a workaround.</p>
  
  <pre><code>&lt;meta http-equiv="X-UA-Compatible" content="IE=EmulateIE9"&gt;
  </code></pre>
  
  <p>This make IE 10 and 11 behave like IE 9. </p>
  
  <p>But my website work only in IE 10+. So this solution isn't suitable to me.
  Is there any other way to solve this issue?</p>