Built-in HTTP related functions previously listed on this page can be found in the networking category.
If you want to make outgoing http connections with php, concider the curl extension.
Regarding what the guy before said. We've experienced problems where certain firewalls have encrypted the HTTP_REFERER meaning that it doesnt always contain the place you've come from.
Better to track where the user has come from either in a form post or in the url.
in reference to toashwinisidhu's and breaker's note, a more effective way would be to use meta-tag redirect, for example.
$url = "http://somesite.com/index.php"; // target of the redirect
$delay = "3"; // 3 second delay
echo '<meta http-equiv="refresh" content="'.$delay.';url='.$url.'">';
The meta goes in the head of the HTML.
The method given below may not sometimes work.
The following method has always worked with me:
just put the following 3 lines in your PHP code
$sec is the time in second after which the browser would automatically go to the url. Set it to 0 if you do not want to give any time.
You can use this function on the events of various html/form objects (eg.-onclick for button).eg.
<input type=button value="Go to Php.net" onclick=setTimeout("location.href='php.net'",0)>
Use this to one step back
<input type="button" value="Back" onclick=history.go(-1)>
You'll usually access variables from forms sent via POST method by just accessing the associated PHP global variable.
However, if your POST data is not URI encoded (i.e., custom application that's not form-based) PHP won't parse the data into nice variables for you. You will need to use $HTTP_RAW_POST_DATA to access the raw data directly. (This should return a copy of the data given to the PHP process on STDIN; note that you wan't be able to open STDIN and read it yourself because PHP already did so itself.)