title: Opacity of div container with background-color style
body: <p>I have a fix colorstring like "#ff0000" and I set this fix string like this (with AngularJS):</p>
  
  <pre><code>&lt;div style="background-color: {{chatMessageOfUser.color}};"&gt;...
  </code></pre>
  
  <p>Now I will set an opacity only to the <code>background-color</code>. Actually I dont know how to do this without splitting the <code>chatMessageOfUser.color</code>- string?</p>