title: Select jquery object by data attribute
body: <p>My html fragment goes something like </p>
  
  <pre><code>&lt;button data-file="day"&gt;Day&lt;/button&gt;
  &lt;button data-file="night"&gt;Night&lt;/button&gt; 
  </code></pre>
  
  <p>and I'm trying to do the following in Jquery </p>
  
  <pre><code>var $button = $('button');
  $button.data('file' , 'day').attr('disabled', 'disabled');
  </code></pre>
  
  <p>So make jQuery objects of all buttons then disable the button with data attribute day</p>