title: PHP Session data clears after form submit
body: <p>I'm storing session data in $relnum variable, as shown below:</p>
  
  <pre><code>if (!isset($_SESSION)) {
      session_start();
      $_SESSION['releasen'] =$_POST['release_no'];
      $relnum=  $_SESSION['releasen']; 
  }
  </code></pre>
  
  <p>And displaying it in form text field, as shown below;</p>
  
  <pre><code>&lt;input name="relnu" id="relnu" type="text" value="&lt;?php if ($rel==''){ echo $relnum;} else echo $rel; ?&gt;" readonly="true"/&gt;
  </code></pre>
  
  <p>I am submitting above Form data in mysql, as shown below;</p>
  
  <pre><code>if (isset($_POST['submitM']))  {
      $faultd=$_POST['faultdistribution'];
      $faultdes=$_POST['faultdescription'];
      $faultsev=$_POST['faultseverity'];
      $faultt=$_POST['faulttype'];
      $faultn=$_POST['faultcmnt'];
      $rel=$_POST['relnu'];
      $query = mysql_query("INSERT INTO `fault` (`fault-cmnt`,`fault-type`, `release_no`, `fault-discription`, `fault-severity`, `fault-distribution`) VALUES ('$faultn','$faultt', '$rel', '$faultd', '$faultsev', '$faultdes')")
          or die(mysql_error());
      echo "Data Added sucessfully";
  }
  </code></pre>
  
  <p>The data is successfully submitted, but after that $relnum variable displays nothing. I am unable to comprehend what is the reason, as i am storing the data in session.</p>
  
  <p>P.S: I am not using unset.</p>
  
  <p><strong>Please help, what i am missing?</strong></p>