title: "Syntax error, unrecognized expression: li." on ie8 when trying to select element via variable class name
body: <p>I'm trying to select several list elements based on a variable in the jquery selector like so:</p>
  
  <pre><code>    var testCase = jQuery.trim('li.' + $.trim(menu_type));
      $('#sidebar-wrapper').find(testCase).show();
  </code></pre>
  
  <p>menu_type is a variable produced earlier in the code.</p>
  
  <p>it works fine on firefox/chrome/safari but not on ie8...
  I searched on google and here for this problem, but didn't find a solution that worked for me. :(</p>
  
  <p>edit: here is more code, explaining what i'm trying to do (sorry for the little information before):</p>
  
  <pre><code>    $('select#menu_select_event').change(function(event) {
      var menu_type = "";
      var $classList = $(this).find(":selected").classList();
      for (var i = $classList.length - 1; i &gt;= 0; i--) {
          if ($classList[i].length &gt; 4 &amp;&amp; $classList[i].substr(-4) === "Menu") {
              menu_type = $classList[i];
          };
      };
      var testCase = jQuery.trim('li.' + menu_type);
      $('#sidebar-wrapper').find(testCase).show();
      $('#sidebar-wrapper').find(testCase).first().find('a').trigger('click');
      $('#sidebar-wrapper').find('li').not('.' + menu_type).hide();
      if (menu_type == 'allMenu') {
          $('#menu_type_explanation').text("通常と弁当メニュー");
      }　else {
          $('#menu_type_explanation').text(jpfy($.trim(menu_type)) + "メニュー");
      }
  
  });
  </code></pre>
  
  <p>classList() is a jquery plugin I wrote.
  What I just found out: menu_type is actually empty on ie8, so I think </p>
  
  <pre><code>$(this).find(":selected")
  </code></pre>
  
  <p>doesn't work on IE8? Is there something else I could use that definitely works on IE8 as well?</p>