title: How can I check whether line-clamp is enabled?
body: <p>I have a dynamic text in a span. I would like to use <code>line-clamp: 2</code>.</p>
  <p>In that case there are max. 2 lines of text and the rest is truncated by <code>…</code>.</p>
  <p>That works with:</p>
  <pre><code>  display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
  </code></pre>
  <p>My problem: If the content is truncated, a tooltip should be displayed. How can I detect whether the text is clamped?</p>
  <p>The height of the element is the same, <code>innerHTML</code> is same... I have no further idea...</p>