强制页面从服务器重新加载而不是加载缓存版本

Question

I have webpage A. The user clicks on a form to submit data, and it takes him to webpage B. When he clicks the back button, I need webpage A to be refreshed from the server, rather that loaded from cache. I have this: <meta http-equiv="expires" content="0"> but it doesnt seem to work. I have also tried setting a variable on page B (session variable via php) and then check for it on page A and refresh (or not) according to its existence. This doest seem to work either. The basic code for that is: Page A:

<?php 
if(isset($_SESSION['reloadPage'])) {
unset($_SESSION['reloadPage']);
echo'
<script>
window.location.replace("/****/****/*****.php");
</script>
';
}
?>

And on page B:

$_SESSION['reloadPage'] = 1;

With the PHP solution, it simply keeps trying to refresh the page in a never ending loop. Something in my logic missing? Is this the right way to go about it?

EDIT Upon further investigation, when you tell the browser to not cache the page, does that force a full server side refresh as well? That's what I need. A full server side refresh of the page.

Answer 1

OK try this instead:

<?php
    if(!session_id()) {
        @session_start();   
    }
    header('Expires: Sat, 26 Jul 1997 05:00:00 GMT');
    header('Last-Modified: ' . gmdate( 'D, d M Y H:i:s') . ' GMT');
    header('Cache-Control: no-store, no-cache, must-revalidate');
    header('Cache-Control: post-check=0, pre-check=0', false);
    header('Pragma: no-cache'); 

    if(isset($_SESSION['form_submitted'])) {
        unset($_SESSION['form_submitted']);
        header('Location: ?' . uniqid());
        #header('Refresh: 0');
    }
?>

You will need to set $_SESSION['form_submitted'] = true on page 2.

Answer 2

Try with all three:

<meta http-equiv="cache-control" content="no-cache"> <!-- tells browser not to cache -->
<meta http-equiv="expires" content="0"> <!-- says that the cache expires 'now' -->
<meta http-equiv="pragma" content="no-cache"> <!-- says not to use cached stuff, if there is any -->

Answer 3

<?php 
    session_start();
    if(isset($_SESSION['reloadPage'])) {
        unset($_SESSION['reloadPage']);
           //no outputting code above header
        header("Cache-Control: no-cache, must-revalidate");
        header("Expires: Sat, 26 Jul 1997 05:00:00 GMT");
        header("Location: http://www.mypage.com/");
    }
?>

Answer 4

I know this is old question and already have the answer (that not refreshing from the server). So I would like to share a solution using jQuery.

$('#back-button').click(function(){
   setTimeout(location.reload(true), 1000);
});

Explanation:
As you click the back button, the setTimeout will triggered after 1 second (1000 milliseconds). Then, the page will reload from the server as the parameter inside the reload is true .

If you put true inside the reload it will reload from the server while if you put false it will reload from the cache. Source w3schools .

Answer 5

Your JavaScript should be...

window.location = "/****/****/*****.php"

I think that should fix your loop.

Answer 6

<?php 
  session_start();
  if(isset($_SESSION['reloadPage'])) {
  unset($_SESSION['reloadPage']);
  echo'
  <script>
  window.location.replace("/****/****/*****.php");
  </script>
  ';
}
?>