$(document).ready(function(){
  // trick from http://lab.pxwebdesign.com.au/jquery/validate-multiple-forms-with-same-class-with-jquery-validator/18
  $.validator.setDefaults({ 
    rules: {
      "comment[comment]": {
        required: true,
      },
    },
  });

  $('.commentForm').each( function(){
    $(this).validate();
  });
});