Proper ampersand handling in e-mail activation link

Question

In e-mail activation links I return

<a href="http://www.foo.com/register.php?action=activation&key=123">Activation</a>

In some clients (eg SquirrelMail) & is changed to & which breaks the link.

<a href="http://www.foo.com/register.php?action=activation&amp;key=123">Activation</a>

How can I make sure the link is displayed correctly in all e-mail clients?

Answer 1

Have you tried URL-escaping the ampersand?

<a href="http://www.foo.com/register.php?action=activation%26key=123">Activation</a>

FWIW, the

<a href="http://www.foo.com/register.php?action=activation&key=123">Activation</a>

is a perfectly fine bit of HTML data, and i believe your issue is actually showcasing a bug in SquirrelMail.