note 57980 added to reserved.variables

Hy everybody! I am a beginer in php I have this: http://127.0.0.1/ovidiu/RP/ produse/index.php? op=prod_list&id_cat=1 and i want to change the language to english for example, How can i do this thing to remain in this page but change the language? I try this href="<?=$PHP_SELF."?lang=en&".$QUERY_STRING;?>" but I have a repetition in the link like: http://127.0.0.1/ovidiu/RP/ produse/index.php?lang=en&lang=en&lang=en& op=prod_list&id_cat=1 every once click the language icon. Thanks! ---- Manual Page -- http://www.php.net/manual/en/reserved.variables.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+57980 Delete: added to the manual -- http://master.php.net/manage/user-notes.php?action=delete+57980&report=yes&reason=added+to+the+manual Delete: bad code -- http://master.php.net/manage/user-notes.php?action=delete+57980&report=yes&reason=bad+code Delete: spam -- http://master.php.net/manage/user-notes.php?action=delete+57980&report=yes&reason=spam Delete: useless -- http://master.php.net/manage/user-notes.php?action=delete+57980&report=yes&reason=useless Delete: non-english -- http://master.php.net/manage/user-notes.php?action=delete+57980&report=yes&reason=non-english Delete: already in docs -- http://master.php.net/manage/user-notes.php?action=delete+57980&report=yes&reason=already+in+docs Delete: other reasons -- http://master.php.net/manage/user-notes.php?action=delete+57980&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+57980&report=yes Search -- http://master.php.net/manage/user-notes.php