PHP Get next page next page URL

PHP Get previous page previous page URL
As the title shows
For example:
Link to b.php from a.php Point

B.php submitting a form to c.php

Want to get a.php link and query note string (ie get) parameters in c.php.

Do not know there is no good way, of course, in the b.php with the session to save the link address in the A.php?query and the query string,
But feel this method is not too good, consult everybody.

------Solution--------------------
When submitting the form in b.php, submit the "to a.php link and query note string (i.e. get) parameter" to the past, put the Hiden tag
------Solution--------------------
There is no other way but to bring the

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