[check if a person is online]

It wont, but it wont have to because the last time the database will update for that person is when they loaded the last page, and that is the time you are comparing to NOW.

 

So if their last page load time is X minutes earlier than NOW, you can assume they are offline.

[Passing a url variable in the url]

<a href="http://domain.com/test2.php?testvar=<? echo $testurl; ?>">test2.php</a>[/code]

sorry dude
Array ( [testvar] => mytest )

 

test2.php:

$testurl = $_GET['testurl'];

 

Testurl does not equal testvar

 

you are passing testvar as your $_GET but not looking for that var in your test2 page, instead you are looking for testurl which doesnt exist because your are using testvar.

 

either change testvar in your url link to testurl or vice versa and you'll work

<? 

if (isset($testurl)) {    // because you have already made $testurl you dont need the $_GET anymore
echo $testurl;
echo '<br>';
}
else {
echo "sorry dude"; 
echo '<br>';
}

print_r($_GET);

?>

</body>
</html>