how to return javascript in a php class file ? -

i want following javascript code echoed in php class file. how can achieve that?

echo '<script language="javascript" type="text/javascript">'."\n";         echo 'var pardoc = window.parent.document;';         if ($result == 'ok') {         echo 'pardoc.getelementbyid("picture_error").innerhtml =  "";';         }         else {         echo "pardoc.getelementbyid('picture_error').innerhtml = '".$result_msg."';";         }          if($filename != '') {         echo "pardoc.getelementbyid('picture_preview').innerhtml = '<img src=\'$preview_url$filename\' id=\'preview_picture_tag\' name=\'preview_picture_tag\' width=\'60\' />';";         }          echo "\n".'</script>';         exit(); // not go futher 

<?php  ?> <script language="javascript" type="text/javascript"> var pardoc = window.parent.document; <?php if ($result == 'ok') {      ?>            pardoc.getelementbyid("picture_error").innerhtml =  "";     <?php  }  else {     ?>      pardoc.getelementbyid("picture_error").innerhtml = "<?php echo $result_msg;?>";     <?php }  if($filename != '') {       ?>       pardoc.getelementbyid("picture_preview").innerhtml = '<img                                      src=\'<?php echo $preview_url.$filename;?>\'                                      id=\'preview_picture_tag\'                                      name=\'preview_picture_tag\'                                      width=\'60\' />';       <?php         }        ?>         </script>         exit(); // not go futher