title: Change the width of a frame according to the width of the other elements
body: <p>I have an <code>div#in</code> and I want the width of my iFrame to fill the rest of the <code>div#di</code> space if the width of the <code>div#in</code> changes
  Friends, how can I do this?</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>#di{
    display: flex;
    border:1px solid red;
  }
  #in{
    display: block;
    border:1px solid blue;
    height: 56px;
    width: 50px;
    resize: both;
    overflow: auto;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"&gt;&lt;/script&gt;
      
      
      &lt;div id="di"&gt;
          &lt;div id="in"&gt;test by change witdh&lt;/div&gt;
          &lt;iframe src="https://www.bing.com"&gt;&lt;/iframe&gt;
      &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>