enter.js

$(document).keydown(function(e) {
    if (e.keyCode === 13) {
      $target = $(e.target);
      if ($target.hasClass('whatever-class')) {
        var $button = $target.siblings('span').find('button');
        if(!$button.is(':disabled')) {
          $button.click();
        }
      }
    }

});