title: CSS vw and percentage value convert to pixel value
body: <p>How do we know that how many pixels in <code>width:100%</code>  and <code>width:100vw</code> ?</p>
  
  <p><strong>Situation</strong> </p>
  
  <pre><code>body{
   width:100%;
  }
  .container{
    width:1000px;
  }
  </code></pre>
  
  <p>How do i get exact value ? </p>
  
  <pre><code>balanceWidth = bodywidth - containerwidth
  </code></pre>
  
  <p><em>I know about css calc <code>width: calc(100% - 1000px);</code></em>  ,  I need to get exact pixel value </p>