title: jquery datatables export rows by class
body: <p>I'm trying to accomplish the following:</p>
  
  <p>create a custom export to get rows which have a certain attribute. In this case the cell 'Payment method' should contain 'check' (I can of course apply a data-attr or class to the cell or row).</p>
  
  <p>What I found so far is to extend the button that way:</p>
  
  <pre><code>"buttons": [
  
                      { 
                          extend: 'pdf', 
                          text: '&lt;i class="sm-close"&gt;&lt;/i&gt;',
                          exportOptions: {
                              columns: [ 0, 1],
                              modifier: {
                                  selected: true
                              }
                          },
                      },         
  ],
  </code></pre>
  
  <p>But that only works for selected rows, which is not what I'm looking for. I lost myself in the very (too) complete documentation of datatables.net... did anyone achieve that already ?</p>
  
  <p>Thanks for pointing me in the right direction !</p>