I have updated this question to make it clearer:
I am sending the word "Über" as the value in a php header as a response to an ajax request like so:
header('title: ' . 'Über');
The word "Über" comes from the database with the columns set as utf8_general_ci and when I echo out the word from the database I see it correctly.
The problem occurs in javascript when I do:
var title = request.getHeader('title');
I then do:
console.log(title);
In Chrome the value of title is correct (Über), but in Safari and Firefox it is converted to "Ãber".
I think that the problem might be that I'm sending the value in the header rather than normal response string.
Any help much appreciated.