Avoid to resent POST or GET on page reloads.
Retun true if reload detected.

To use it, generate a random hash in the form, for example:

<form action="/process" method="GET">
<input name="antireload" type="hidden" value="<?=md5(rand())?>" /> 
email: <input name="email" type="text" value="" />
name: <input name="name" type="text" value="" />
comment: <input name="comment" type="text" value="" />
</form>

 

On the process page, add antiReload to check if F5 was pressed:

 

if (!$wv->antiReload($antireload)) {
    //Code for processing the form.
}