how to use get method in a session? - php

Question

here is my code. actually i am displaying some data from mysql on the page and creating dynamic link.i want started a session with session_start() in the very begining of code before starting any code. i want to store the value of the link that is to be display on other pagepage..
page1.php
<a style="color:#F00; font-family:Arial, Helvetica, sans-serif; margin-left:33px; font-weight:bold">
No. of registered students:
</a>
<table border='1' align="center" style="font-size:14px" width="95%" cellspacing="3" class="db_table">
<tr class="db_table_tr" >
<th class="db_table_th" name="submit">USN</th>
</tr>
<?php
include('includes/login_connection.php');
$query = "select p.usn, p.name from personal_details p, course_codes c where p.usn = c.usn order by p.usn";
$run = mysql_query($query) or die($query."<br/><br/>".mysql_error());
$num = mysql_numrows($run);
echo $num;
while($row = mysql_fetch_assoc($run)){
echo "<tr>";
echo "<td>" . $row['usn'] . "" . "</td>";
echo "<td>" . $row['name'] . " </td>";
if(isset($_GET['submit'])){
$_SESSION['session_usn'] = $_GET['usn'];
}
}
echo "</tr>";
mysql_close($bd);
?>
</table>
page2.php
<?php
session_start();
if(isset($_SESSION['session_usn']))
{
$_POST['usn'] = $_SESSION['session_usn'];
echo $_POST['usn'];
}
?>

Answer 1

You need to provide a fall-back, in case the URL provided does not contain the proper variables in the $_GET section.
You have:
if(isset($_GET['submit'])){
$_SESSION['session_usn'] = $_GET['usn'];
}
You should do something else if $_GET['submit'] isn't set:
if(isset($_GET['submit'])){
$_SESSION['session_usn'] = $_GET['usn'];
} else {
$_SESSION['session_usn'] = "unset";
// or set a warning flag like "unset"
}
You should be feeding your php file a url like:
http://yoururl.com/page1.php?usn='333'
Where 333 is the value you want to store.