Losing form data when clicking the back button on

问题:

This question already has answers here:

Why are HTML forms sometimes cleared when clicking on the browser back button (3 answers)

Closed 3 years ago.

When I click back on any browser I lose all the data which was inputted in the form on both drops downs and text input types.

Is this a server , Browser or a coding issue ?

Thanks

回答1:

Its a browser issue. Browser behave differently when the back button is clicked -- this behavior mostly depends on user privacy settings. In addition, most browsers will automatically reset form upon hitting back button for pages viewed over HTTPS connection regardless of their normal behavior for HTTP connections. In addition, many HTML forms that rely heavily on AJAX do not properly -- or consistently -- restore their previous state.

Edit ----

Now that you mention using PHP and MySQL, assuming that you are also using sessions... the browser will not pre-populate the form when you hit the back button. PHP-session powered pages are not cached in browsers and hitting back button to go back to previous page is just like opening that page again from the very beginning -- most browsers will not bother restoring the form values.

回答2:

This applies to PHP and IE8.

Not only must you set cacheing to private, but you must remove the 4 cacheing headers and this can only be done with PHP 5.3.

In PHP 5.2 you can only set the 4 headers to blank values if using the Zend Framework's setHeader() method. For some reason is not sufficient on IE8 to set the 4 header values to empty values. Here's the code for PHP 5.3:

header_remove("Expires"); 
header_remove("Cache-Control"); 
header_remove("Pragma"); 
header_remove("Last-Modified"); 

回答3:

You need to create sticky forms for the browser to keep form data when back is pressed. Its fairly easy to do, check out the tutorials in the search linked.