title: How do I manipulate a jqGrid's search/filters?
body: <p>I have a jqGrid with a navBar that has <code>search: true</code> and <code>multipleSearch: true</code>. I would like to add a button to my UI that automatically adds an additional rule to the search.</p>
  
  <p>I've tried manipulating the postData for the filter directly, but values added this way don't show up in the search UI.</p>
  
  <p>I've also tried accessing the search box directly using jQuery, like this:</p>
  
  <pre><code>$('#fbox_list').searchFilter().add();
  $('#fbox_list .sf .data input').each(function(index) {
      alert($(this).val());
  });
  </code></pre>
  
  <p>But, in addition to feeling hackish, it only works if the user has already clicked on the search button (the fbox_list div is not constructed on load).</p>
  
  <p>Has anyone else dealt with an issue like this?</p>