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 tried the onload event for the body element, but it doesn't fire on Firefox or Safari.
I'm working with some old code that tries to prevent double-submission of form data by disabling all form submission buttons as soon as the user clicks one (by listening to the form's onSubmit event). This code is applied to every form in the app, regardless of whether double-submission would even be a problem.
The problem is that if the user hits the back button in Firefox or Safari, all the submit buttons are still disabled when he gets to the page. On Firefox, they are even disabled after a refresh (only a Ctrl+F5 refresh will do it)!
I've tried listening to body 's onLoad event, but FF and Safari don't fire that when you get to the page via back button. (Interestingly, it is fired on a soft refresh on FF, even though the button stays disabled.)
Here's a very simple HTML doc that will show what I mean:
<html><body>
<form name="theForm" id="theForm" action="test2.html"
onSubmit="document.theForm.theButton.disabled = true;">
<input id="theButton" type="submit" name="theButton" value="Click me!" />
</form>
</body></html>
Note: I've tested on WinXP with IE8, FF3.5, Safari 4, Opera 9, and Chrome 2.0. Only Safari and FF leave the button disabled when you use back to get to them.
4 answers
solution1
2 2009-07-15 21:15:56
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.
solution2
2 2009-07-15 21:18:11
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.
solution3
1 ACCPTED 2009-07-15 21:13:11
我不认为你可以专门测试后退按钮，但我相信你可以用Javascript查看浏览器的历史记录位置。
solution4
0 2012-06-20 18:20:20
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';
}
?>
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.