title: jquery get number from id
body: <p>how can i get the number from a div tag's id?</p>
  
  <p>example:</p>
  
  <pre><code>&lt;div id="button1"&gt;&lt;/div&gt;
  </code></pre>
  
  <p>how can i get the 1 and store it in a variable?</p>