Back Button Problem

[gahook]

Please visit this link.

When I click the link ("page2.php?inc=true"), the browser will go to "page2.php" and display "$inc is TRUE!".

My problem is: if I click the Back Button and the Next Button, the broswer will stil display "$inc is TRUE!". But I want to display "$inc is FALSE!" like the user clicking this link, page2.php , directly.

Please help!

Thanks,
Gahook Dinn

[devinemke]

when using the BACK/FORWARD buttons on most modern browsers the exact URL (including query string) will be used.

you could check the $SERVER['HTTP_REFERER'] on page1 and conditionaly strip off the query string from the link. be advised that $SERVER['HTTP_REFERER'] is not very reliable.

[rehfeld]

i assume you only want to display '$Inc is true' 1 time per user?

use either sessions, or cookies to keep track of whether they have visited the page or not.

[Roger_Ramjet]

My understanding of it was that the page will be stored in the browser cache and only reload the page from the server if it has expired. So including headers for no cache or giving it an expiry date in the past would force a reload from the server, otherwise you just get what you had last time.

I stand to be corrected on this, and would like to know if my understanding is wrond.

[gahook]

Thanks for your reply. To be more clear, my question is to:
1. When the user click "page2.php?inc=true" on "page1.htm", the broswer will go to "page2.php" and display "$inc is TRUE!".
2. If the user click "Back/Next" buttons, the "page2.php" won't display "$inc is TRUE!", but show "$inc is FALSE!".
3. When the user go to "page1.htm" and click "page2.php?inc=true" again, "$inc is TRUE!" will be shown on "page2.php" again.

I tried to add the following codes:
page1 (of course, I changed the file type from HTM to PHP):

session_start();
if (!session_is_registered("is_shown")) {
    session_register("is_shown");
}
$is_shown = false;

page2:

session_start();
if (!session_is_registered("is_shown")) {
    session_register("is_shown");
    $is_shown = false;
}

and modify the code as:
if ($is_shown)
    $inc = false;

if ($inc) {
    echo "<h1>\$inc is TRUE!</h1>";
    $is_shown = true;
} else {
    echo "<h1>\$inc is FALSE!</h1>";
}

But the problem is still existed. I don't know why this doesn't work. Please help!

Many thanks,
Gahook Dinn

[rehfeld]

unless your using an old version of php that does not support the new session sytax,
you should avoid using session_register and the like. the new syntax is much easier imo anyway.

also, its a good idea to write you code so it does not require register_globals to be turned on, like so:

<?php

header('Cache-control: nocache');

session_start();

if (!empty($_GET['inc']) && !isset($_SESSION['inc_flag'])) {
    echo '$inc is true';
    $_SESSION['inc_flag'] = true;
} else {
    echo '$inc is false';
}







?>

[gahook]

Thanks for your suggested codes. It works for clicking "Back/Next" buttons.

But if I click the link "page2.php?inc=true" on the page1 directly again, the page2 can't display "$inc is FALSE!" correctly. Who could I resolve it?

Please visit:
1. page1.htm
2. page1.php
3. page2.php

Thanks a lot,
Gahook Dinn

[gahook]

Hi all,
Please help me to solve this problem.
Thanks a lot,
Gahook Dinn