I'm trying to do a regex find replace on a load of links that contain foreign characters such as ä and replacing them with their encoded version %C3%A4.

For example. I would want to replace
<a href="wähle.html">Wähle</a>
to
<a href="w%C3%A4hle.html">Wähle</a>

Can anyone tell me how I do this?