title: Accessing input names with array pattern jQuery
body: <p>I'm trying to access, via jQuery, the following input names in order to change their state properties based on a group of possible options. The markup is the following:</p>
  
  <pre><code>&lt;input name="extra[00]" id="extra[00]" type="text" class="optional-field extra " value="" disabled="disabled"&gt;
  &lt;input name="extra[01]" id="extra[01]" type="text" class="optional-field extra " value="" disabled="disabled"&gt;
  &lt;input name="extra[02]" id="extra[02]" type="text" class="optional-field extra " value="" disabled="disabled"&gt;
  &lt;input name="extra[20]" id="extra[20]" type="text" class="optional-field extra " value="" disabled="disabled"&gt;
  &lt;input name="extra[21]" id="extra[21]" type="text" class="optional-field extra " value="" disabled="disabled"&gt;
  &lt;input name="extra[30]" id="extra[30]" type="text" class="optional-field extra " value="" disabled="disabled"&gt;
  </code></pre>
  
  <p>The first digit in name="extra[XX]" states a group and that's why it may repeat, while the second sets the order. I was trying this, but can't find a way to get the second possible element: </p>
  
  <pre><code>var id = jQuery(this).val(); // Changes from a drop-down
  var extra = jQuery('input[name="extra[' + id + ']"]');
  </code></pre>
  
  <p>Is it possible to count how many "extra" elements are in the DOM starting, for instance by the id=2 (<code>jQuery('input[name="extra[2*]"]')</code>) ?</p>
  
  <p>Thank in advance for any help.</p>