title: Where does this inaccuracy with DOM scroll events come from?
body: <p>Have a look at the code below, there is a jsbin for it too here: <a href="http://output.jsbin.com/qosevogeka/" rel="nofollow noreferrer">http://output.jsbin.com/qosevogeka/</a></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-js lang-js prettyprint-override"><code>var container = document.querySelector('.container')
  var firstEventHandled = false
  container.addEventListener('scroll', function(e) {
    if (firstEventHandled) return
    console.log(e.target.scrollLeft)
    firstEventHandled = true
  })</code></pre>
  <pre class="snippet-code-css lang-css prettyprint-override"><code>.container {
    display: flex;
    overflow: scroll;
  }
  
  .box {
    flex-shrink: 0;
    width: 40%;
    height: 50px;
    background: yellow;
  }
  
  .box+.box {
    margin-left: 15px;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;body&gt;
    &lt;div class="container"&gt;
      &lt;div class="box"&gt;
      &lt;/div&gt;
      &lt;div class="box"&gt;
      &lt;/div&gt;
      &lt;div class="box"&gt;
      &lt;/div&gt;
      &lt;div class="box"&gt;
      &lt;/div&gt;
      &lt;div class="box"&gt;
      &lt;/div&gt;
      &lt;div class="box"&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/body&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>If you scroll the resulting view, you will see that <code>0</code> is never logged to the scroll which I expect since the <code>scrollLeft</code> was <code>0</code> before I started scrolling. Where does this inaccuracy with the scroll events come from? Thanks</p>