Sessions variables disappearing?

[Dolemite50]

Hi,
I am new to sessions and they seem to be working but it appears that after a few pages the variables disappear. What do I need to be looking out for here?

I tried putting session start(); at the top of every page but its not working. Do I also need to redeclare the variables on every page? Will it lose these variables if I don't? I think I tried adding

<$php
session_start():
$loginName = $_SESSION['loginName'];
?>

to every page but on a few pages if i echo $loginName it is blank.

On this scenario, if I have the above code on the top of the page, and then later in the script I pull $loginName from a DB, and then on the next page I have the above code again, wouldnt it default to use the session variable?

Any hints would be appreciated.

[eli03]

do you declare a value for $_SESSION['loginName'] ?

try this
page1.php

<?
session_start();


$he='hello world';
$_SESSION['name']="$he";
echo "$_SESSION[name]<br>";
echo "<a href=page2.php>>>pass hello world to next page</a>";


?>

page2.php

<?
session_start();

echo "session -->".$_SESSION['name']. "<-- should display hello world, if not, session not passed<BR>";

echo "<a href=page3.php>>>DESTROY SESSION</a>";


?>

page3.php

<?
session_start();

$variable = $_SESSION['name'];
unset( $_SESSION['name'], $variable );
echo "$variable";
echo "<a href=page1.php>>>back page1</a>";

?>