title: jquery attr() do not work in IE
body: <p>I use jquery to do some thing, and I use <code>attr()</code> method to get the <code>id</code> attribute, and it works well in Chrome and Firefox, but not in IE9 and Opera, some of the code is like: </p>
  
  <pre><code>parent = $(this).parents('.every_note');        
  loan_id = parent.attr('id');
  </code></pre>
  
  <p>in the line </p>
  
  <pre><code>loan_id = parent.attr('id');
  </code></pre>
  
  <p>Opera said: <code>Unhandled Error: 'parent.attr' is not a function</code>, 
  and in IE said: <code>does not support attr() method or attribute</code>.</p>
  
  <p>But i can use this method if I test it in the browser's console ,
  so anyone can tell me why？ thanks </p>