Return values from CI controllers to Javacript (jQuery)

[eluser]MaartenDeGroote[/eluser]
I figured this one out. Well, not exactly but I found a solution.
All i did was changing the following code:

Code:

$(document).ready(function(){
    $("form").submit(function(){
        var str = $(this).serialize();
        $.ajax({
            type : "POST",
            url : "ajax/form",
            data : str,
            success : function(msg){
                alert(msg.message)
            }
        }, "json");
        return false;
    });
});

to

Code:

$(document).ready(function(){
    $("form").submit(function(){
        var str = $(this).serialize();
        $.ajax({
            type : "POST",
            url : "ajax/form",
            data : str,
            dataType : "json",
            success : function(msg){
                alert(msg.message)
            }
        });
        return false;
    });
});

Now it works perfectly.