Page expired when you hit back

[dwx]

Does anyone know why...
When you submit a form, and then you hit the browser's back button

On some forms/pages - hitting back shows the form with your previous input

On other forms/pages - hitting back displays a "this page has expired" message instead?

I've seen this effect in both ASP pages and PHP pages I've written - is there any way to control what is displayed?

Thanks

[ncrossland]

i believe (possibly wrongly?) that forms sent by GET are visible when you go back (in IE) and forms sent by POST need to be reposted.

[dwx]

I don't think so - I only ever use POST on forms I've written.

Bizarre though - if I use IE6 I get the page expired, but using Mozilla Firebird on the same pages, I do not.

In the past I've seen it occur more on PHP pages than ASP.

Hmmmn.

[Andy]

It's specific to IE. AFAIK no other browsers have the 'problem'. Nick is also right about POST and GET.

GET will not produce the dialog, but POST will. Reason being: GET means the data is sent as a URL query string (so IE has a record of it in the address bar) but POST doesn't so without re-submitting the page it would technically be showing you an cached version of something which is supposed to be dynamic - hence the dialog (it would be nice to be able to select "dont remind me again" on the dialog though).

Sadly POST is the better method for submitting forms and in some cases is technically required.

Complain to MS! :)

[dwx]

aha...

But not on all versions/configs of IE? I've got 2 machines that don't complain.

It's the weekend now though. Maybe Freeserve will announce they're bundling Mozilla or Opera with all their CDs in future and insist all users upgrade.

[Andy]

Sometimes it can be affected by the caching settings of IE. 'Every Visit', 'Every Start', 'Always', 'Never'. I believe if you tweak these then you can prevent it asking you.

You might get some other undesired effects though.

[cscarlet]

i dislike mozilla, one of my admins coded something buggy as hell and it was ok for him cos mozilla fixed it but in ie it won't fix it