subpanel filter (it works!)- critique needed

[Francescas]

We wanted users to be able to search within the subpanel without leaving the page.

To achieve this I created a SugarWidget as follows:

<?php
if(!defined('sugarEntry') || !sugarEntry) die('Not A Valid Entry Point');
//error_reporting(E_ALL);
//ini_set('display_errors', 'On');
require_once('include/generic/SugarWidgets/SugarWidgetSubPanelTopButton.php');

class SugarWidgetSubPanelTopFilterInputButton extends SugarWidgetSubpanelTopButton
{
   function SugarWidgetSubPaneliFilterInputButton($button_properties=array())
      {
          $this->button_properties=$button_properties;
      }

function display(&$widget_data){
      $subpanel_definition = $widget_data['subpanel_definition'];
      $subpanel_name = $subpanel_definition->get_name();
      $module_name = ($_REQUEST['module']?$_REQUEST['module']:'');
      $id = ($_REQUEST['record']?$_REQUEST['record']:'');
      $prior_search_params[$subpanel_name] = trim($_REQUEST['search_params']?$_REQUEST['search_params']:'');
      if (isset($prior_search_params[$subpanel_name]) && $prior_search_params[$subpanel_name] != ''){
         echo("&nbsp;<i>Filter Applied:</i><b> " . $prior_search_params[$subpanel_name] . "  </b> <small>(click Filter with no parameters to remove filter)</small>");
      }
      $button = "<form><input type='text' id='filter_param_" . $subpanel_name . "' name='search_params' value='" . $prior_search_params[$subpanel_name] . "'>";
      $button .= "<input type='submit'  onclick=\"current_child_field = '" . $subpanel_name ."';
                                                  url='index.php?sugar_body_only=1&module=$module_name&subpanel=$subpanel_name&entryPoint=filter_subpanel&inline=1&record=$id&layout_def_key=$module_name&search_params=' + escape(document.getElementById('filter_param_' + current_child_field).value) ;
                                                  showSubPanel('".$subpanel_name ."',url,true,'" . $module_name . "');
                                                  document.getElementById('show_link_" . $subpanel_name . "').style.display='none';
                                                  document.getElementById('hide_link_" . $subpanel_name . "').style.display=''; 
                                                  return false;
                                                \" 
                   href='#' value='Filter'></form>";
      return $button;
   }
}

?>

The custom entry point filter_subpanel.php is a modified version of include/SubPanel/SubPanelViewer.php where the subpanel definition is manipulated to set the where clause.