title: Check if string "starts with" another string
body: <p>I want to check if an address starts with <a href="http://www.youtube.com" rel="nofollow noreferrer">http://www.youtube.com</a>.</p>
  <p>If I have something like this</p>
  <pre><code>if rs(&quot;mainVideoName&quot;)=&quot;http://www.youtube.com*&quot; then
  </code></pre>
  <p>This doesn't work, so how can I do it?</p>