title: Enable/Disable button based on count of multiple checked checkboxes all with different ID's
body: <p>I have a list of checkboxes in a table like this along with a button:-</p>
  
  <pre><code>&lt;table id="mytable"&gt;
  &lt;tr&gt;&lt;th&gt;checked&lt;/th&gt;&lt;th&gt;id&lt;/th&gt;&lt;th&gt;text&lt;/th&gt;&lt;/tr&gt;
  &lt;tr&gt;&lt;td&gt;&lt;input id="cb1" type="checkbox" name="checker1"/&gt;&lt;/td&gt;&lt;td&gt;123&lt;/td&gt;&lt;td&gt;abc&lt;/td&gt;&lt;/tr&gt;
  &lt;tr&gt;&lt;td&gt;&lt;input id="cb2" type="checkbox" name="checker2"/&gt;&lt;/td&gt;&lt;td&gt;456&lt;/td&gt;&lt;td&gt;def&lt;/td&gt;&lt;/tr&gt;
  &lt;tr&gt;&lt;td&gt;&lt;input id="cb3" type="checkbox" name="checker3"/&gt;&lt;/td&gt;&lt;td&gt;789&lt;/td&gt;&lt;td&gt;ghi&lt;/td&gt;&lt;/tr&gt;
  &lt;tr&gt;&lt;td&gt;&lt;input id="cb4" type="checkbox" name="checker4"/&gt;&lt;/td&gt;&lt;td&gt;454&lt;/td&gt;&lt;td&gt;ghi&lt;/td&gt;&lt;/tr&gt;
  &lt;tr&gt;&lt;td&gt;&lt;input id="cb5" type="checkbox" name="checker5"/&gt;&lt;/td&gt;&lt;td&gt;565&lt;/td&gt;&lt;td&gt;ghi&lt;/td&gt;&lt;/tr&gt;
  &lt;/table&gt;
  
  &lt;input type="button" name="myjqbutton" value="My Jquery Button" id="jqb" disabled="true"/&gt;
  </code></pre>
  
  <p>What i want to do is, only enable the button if 1 or more checkboxes are checked.</p>
  
  <p>Initial thoughts are that I need to count the amount of checkboxes checked in the table, I can do this using a .each to count them into a variable.</p>
  
  <pre><code>var mytable= document.getElementById('mytable');
  $('input:checkbox:checked', mytable).each(function() {
  // whatever here
  });
  </code></pre>
  
  <p>However, each checkbox will need a changed event to check the count and enable or disable the button depending if count > 0 or not.</p>
  
  <p>Or is there an easier way of achieving this functionality I am looking for.</p>