$(document).ready(function() {

   $("#searchbox").keydown(function(e) {

      if(e.keyCode != 13){
          return true;
      }

      var isInIFrame = (window.location != window.parent.location) ? true : false;

      if(isInIFrame) {
        window.parent.location = 'index.php?id=13&&tx_indexedsearch[sword]=' + $(this).val();
      }else {
        window.location = 'index.php?id=13&&tx_indexedsearch[sword]=' + $(this).val();
      }
   });

});