Passing variable to outgoing link

[awakedesignstudios]

hi world, im new to php so bare with me.  a site im developing requires the ability to pass a variable to a link when its clicked.  what i mean by this is when a link is clicked, php grabs a variable and sticks it in the link, for tracking which user logged into my site clicked the link.

[ignace]

print '<a href="http://domain/page.php?user=' . $_SESSION['username'] . '">click</a>';

[awakedesignstudios]

so $_SESSION would be the variable thats storing the username? or username storing the variable, and $_SESSION is inputting it into the link?  im new to this php world....somehow i need to store a variable based on the user that is logged in, and pass the user variable into the link when its clicked...so if

print '<a href="http://domain/page.php?user=' . $_SESSION['username'] . '">click</a>';

puts the username into the link, how would i store the user variable in the first place?

[awakedesignstudios]

what im asking is how should i store the usernames variable in the first place?

[ignace]

$_SESSION['username'] = $_POST['username'] for example

[awakedesignstudios]

so use a form?  doesnt that mean the very next page has to be the link one?  if im going to use the username var on different pages, will POST remember?  someone on another forum suggested i use cookies to store the username.  im using this in joomla, so i think i have the edit the built in login module to track the username coookie somehow, not sure how yet though.  do u know anything about customizing joomla and its extensions?

[gamesmstr]

Session variables stay active in the current session until the session is closed.  No need to recall them on every page.

[waynew]

Also, do make sure to sanitize the output of $_SESSION['username'] using htmlentities!