Sommige websites informatie te sturen naar hun servers. Firefox houdt een kopie van wat je in de website opgenomen, maar wil ervoor zorgen dat u opnieuw wilt verzenden. Bijvoorbeeld, als u het invullen van een enquête, afwerking, en ga dan terug, wordt u gevraagd of u wilt al die informatie opnieuw te verzenden. Het is gewoon een zekerheid ding.

P.S. Ik hoop dat de vertaling niet te ruw.

**ENGLISH TRANSLATION**

Question Title: one page back, and the document has expired

Details: why does firefox every time I go back a page that the document has expired and must reconnect.

My reply: Some websites send to their servers information. Firefox keeps a copy of what you entered in the website, but want to make sure you want to send again. For example, if you are filling out a survey, finish, and then return, you will be asked if you want to send all that information. Again It's just a security thing.

P. S. I hope the translation is not too rough.

You can get a "document has expired" message if you use the back button or a bookmark to go back to a specific page and the web site has instructed Firefox not to cache the page. Firefox tries to retrieve the page from the server, possibly by sending POST data that is no longer valid. In such a case best is to open links from such a page in a new tab/window by middle-clicking a link to avoid using the Back button, but instead close the tab to return to the previous tab.

Thx for the answers.