Can I detect when a user gets to a page using the back button?

Question

Edit: What I really need to know is if there is any javascript event that will reliably fire when the user arrives at the page via the back button. I trie

Answer 1

I don't think you can test for the back button specifically, but I believe you can check the browser's history position with Javascript.

Answer 2

The answer by @tkotitan was probably correct when he wrote it. His answer led me to my solution. It's not foolproof, but it might be "good enough" to help in some situations.

I improved my script and replaced it with the following. This version is for an intermediate page that now works as intermediate in both directions.

<?php
if($_SERVER['QUERY_STRING']=='')
{
    echo '<a href="go_back_test.php?page=1">Go forward</a>';
}
elseif($_GET['page']!=2)
{
    echo 'You cannot stay here.';
    echo '
    <script type="text/javascript">
    function test()
    {
        if (document.getElementById("detectback").value=="goneback")
        {
            document.getElementById("detectback").value=history.length;
        }
        if (document.getElementById("detectback").value==history.length)
        {
            document.getElementById("detectback").value="goneforward";
            window.location = "go_back_test.php?page=2"
        }
        else
        {
            document.getElementById("detectback").value="goneback";
            window.history.back();
        }
    }
    function updateform()
    {
        if(document.getElementById("detectback").value=="")
        {
            document.getElementById("detectback").value=history.length;
        }
    }
    </script>
    <img src="spacer.gif" onload="updateform(); test();"><br>
    <form>
        <input id="detectback" type="text" value="" style="display: none;">
    </form>
    ';
}
else
{
    echo 'Welcome to page 2';
}
?>

Answer 3

Yes. In javascript you can use visited.value

function checkrefresh()
 var visited = getCookie("visited");  
{
        if((form.visited.value == '' || form.visited.value == null) && (visited != '1') ) 
        {
            document.form.visited.value = "1";
                    document.cookie = "visited=1";
                    //here you set it to something so that next time they go to the page it will no longer be nothing and you can 'disable the button' see below.

        }
        else
        {
            document.form.submitbutton.disabled=true;
        }
    } 

function getCookie(name)
{
var re = new RegExp(name + "=([^;]+)");
var value = re.exec(document.cookie);
return (value != null) ? unescape(value[1]) : null;
}

you would call this in the onload tag FYI.

Answer 4

Isn't that the behaviour you want, so they don't double-submit using the back button?

Anyway, you could set a cookie on the following page, and detect that on load on the page with the form.