How to display a warning when users leave your site

I received an odd request from my manager recently. He wants to know
if we can warn users who click links that lead to external sites that
they are leaving our site. I am arguing against this on several
grounds, but want to understand all the technical possibilies. I
inherited the site and it is 90% static HTML with some PHP and Perl
applications.

I can think of a few ways to do this:

1. add a javascript onclick() event handler to each link to create a
popup.
2. pass the destination of each link to page that displays a warning,
then redirects the user to the destination.

Is there some obscure global apache setting that lets you trap a
clicked link and send a warning first?

What is the best and easiest way to do this?

TIA for any suggestions.

On Thu, 22 Sep 2005 10:08:22 -0700, nb8nc6 sent:

> I received an odd request from my manager recently. He wants to know if
> we can warn users who click links that lead to external sites that they
> are leaving our site. I am arguing against this on several grounds, but
> want to understand all the technical possibilies. I inherited the site
> and it is 90% static HTML with some PHP and Perl applications.

Surely it'd be too late to "warn" someone as they were "leaving"? If it
were even possible, for which I'm guessing client-side JavaScript would be
the only way of doing that.

The only sensible I can think of doing is to make sure that all of your
external links are *clearly* *labeled* as such.

e.g. We service <a href="http://.......">Panasonic</a> [external link]
television sets.

If you don't like that idea, then about the next best solution is to
*title* the link in a similar way:

e.g. We service <a href="http://......." title="[external link to
Panasonic's website]">Panasonic</a> television sets.

That lets those who care about where they're about to go with a link to
find out, in a way that they usually use to check links (hovering over
them without clicking), but doesn't add extra text to the page.

Scripting isn't going to work for all people, and nagging them not to
leave with requesters is going to annoy them. Don't be tempted to make
external links open up in new windows, that has it's own problems.
Amongst them, it annoys people who don't want yet another window open, and
can cause problems for low spec PCs which already have too many windows
open.

--
If you insist on e-mailing me, use the reply-to address (it's real but
temporary). But please reply to the group, like you're supposed to.

This message was sent without a virus, please destroy some files yourself.

Excellent suggestions, Tim. Thank you. I like labeling the link idea.
It is a nice clean solution. I am against the whole warning popup
idea.

nb8nc6@gmail.com (nb8nc6) wrote in
<1127408902.759862.294560@g44g2000cwa.googlegroups .com>:

>I received an odd request from my manager recently. He wants to
>know if we can warn users who click links that lead to external
>sites that they are leaving our site. I am arguing against this on
>several grounds, but want to understand all the technical
>possibilies. I inherited the site and it is 90% static HTML with
>some PHP and Perl applications.
>
>I can think of a few ways to do this:
[snip]

One commonly-used way to solve this is to replace all your plain HTML
links to external sites with links to a little, local (ie. on your
machine or at least inside your domain) redirector. So a link like
http://www.otherco.com/
becomes
http://www.myco.com/cgi-bin/oco-redi...ww.otherco.com

You can have the redirector either show the warning ("You are about
to leave MyCo's web site") and then automatically redirect, or have
it warn and present the real link, or whatever you like.

....Steve

--
Steve van der Burg
Technical Analyst, Information Services
London Health Sciences Centre
London, Ontario, Canada
Email: steve.vanderburg@lhsc.on.ca

On Fri, 23 Sep 2005, Steve van der Burg wrote:

> One commonly-used way to solve this is to replace all your plain HTML
> links to external sites with links to a little, local (ie. on your
> machine or at least inside your domain) redirector. So a link like
> http://www.otherco.com/
> becomes
> http://www.myco.com/cgi-bin/oco-redi...ww.otherco.com

Indeed. And, discerning users will then suppose that you are rudely
collecting information on their behaviour (in a way that wouldn't have
been possible if you'd just used a direct web link).

In some legislations, I suspect you will require to have a published
privacy policy as to what you're intending to do with those
statistics. IANAL: take legal advice if this concerns you.

Also, if you use a delayed meta...refresh, this is considered
inherently inaccessible, so check the WAI guidelines for acceptable
procedures.

I can't help feeling that, taking all the consequences into account,
one would better dispense with this idea unless there are very
powerful reasons for doing it (e.g Google do this, but they can afford
to do it, as they are delivering a valuable service for free).

Consider whether it wouln't be better to just label the external
links differently than the internal ones, so that users can (if they
wish) see the difference before they take the link.

In article <1127415160.033362.221300@g47g2000cwa.googlegroups .com>,
"nb8nc6" <nb8nc6@gmail.com> wrote:

> Excellent suggestions, Tim. Thank you. I like labeling the link idea.
> It is a nice clean solution. I am against the whole warning popup
> idea.

Slashdot does something handy that is similar by showing the target
domain in brackets. Additionally, you could use CSS to change the
color/style of the links that are external.