How to get the url of the previous page

How can I get the url of the previous page? I use header ('Location :.. /index. php ') jump to index. for php, how can I get the url of the page before the jump? $ _ SERVER ['http _ referer'] may not be supported ., The url is passed during the jump, for example, PHPcode $ pre_url = How to obtain the url of the previous page
I jumped to index. php through header ('Location: ../index. php'). how can I get the url of the page before the jump,
$ _ SERVER ['http _ referer'] does not seem to work.

------ Solution --------------------
The url is uploaded during a jump, for example

PHP code

$ Pre_url = url_encode ('http: // 127.0.0.1/xxx. php'); header ('Location: ../index. php? Pre_url = '. $ pre_url );