title: How to get a part of id element using jQuery?
body: <p>How I can get a "Some text" from span with id="old-[id]" and put it in id="new-[id]" ?</p>
  
  <pre><code>&lt;span id="old-1"&gt;Some text&lt;/span&gt;
  &lt;span id="new-1"&gt;&lt;/span&gt;
  &lt;span id="old-5"&gt;Some text&lt;/span&gt;
  &lt;span id="new-5"&gt;&lt;/span&gt;
  </code></pre>
  
  <p>I don't know how to get a digital part of <code>id</code> without <code>substring()</code> function. 
  I think exists is more correct solution.
  Thanks.</p>