On Thu, Sep 17, 2009 at 3:35 PM, Brady Eidson <[email protected]> wrote:
> On Sep 17, 2009, at 2:17 PM, Ojan Vafai wrote: > > There a plenty of sites that only have a beforeunload handler and have no > reason to register an unload handler. If you're not prompting the user to > stay on the page, the two events are essentially equivalent. > > This is not true. > > I couldn't test IE right now but for Safari, Opera, and Firefox, I just > independently verified that: > -unload handlers prevent a page from going into the page cache. > -beforeunload handlers do not > -beforeunload handlers are called before a page is navigated away from, > even when the page is going into the page cache. > > So the key difference is that while an unload handler will *only* ever run > once, when a page is destroyed, a beforeunload handler might run multiple > times, each time the user navigates away from the page after returning to > it. > > This might not be immediately relevant to the conversation, but they are > not the same and I'd rather the conversation not assume they are. > > In practice, if an author uses beforeunload as their unload handler, they > are doing The Wrong Thing(tm) > Crazy. I didn't know that and I would expect very few web developers do. :) For what it's worth, I've worked on sites that did this. Ojan
_______________________________________________ webkit-dev mailing list [email protected] http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
