Jquery TextArea JSON and Illegal Character - most notably the £

I have a textarea, and am using $('#mytextarea').val(), and when i have text that is '£' i am getting the infamous black diamond with a question mark in it. �, When i package this up as a JSON packet it then gets sent to the server and it interprets it like this: "£" on the server side.

I am sending it to the server with this code:

jQuery.ajax({
        url: "aurl",
        contentType: "application/json; charset开发者_运维技巧=utf-8",
        dataType: "json",
        async : true,
        cache : false,
        type: "POST",
        processData : false,
        data: JSON.stringify(parameterMap)
});

I don't really understand why its just the £ symbol that is causing me issues, is it character encoding? is it server or client side?

Any ideas?

This looks like an encoding issue on server side. E.g. you could add a Filter before your servlet that has a doFilter like this one:

public void doFilter(ServletRequest request, ServletResponse response,
        FilterChain chain) throws IOException, ServletException {
    if (request.getCharacterEncoding() == null)
        request.setCharacterEncoding("UTF-8");
    response.setCharacterEncoding("UTF-8");
    chain.doFilter(request, response);
}

This will also set the correct encoding for the answers the servlet is sending.

Another hint you could check in your project: if you define some String constants in your code, check that the files are in the same encoding while editing and when the server delivers them.