NOTE: Doesn't work on newer versions of jQuery.
Since you are using jQuery please use it's seralize function to serialize data and then pass it into the data parameter of ajax call:
info[0] = 'hi';
info[1] = 'hello';
var data_to_send = $.serialize(info);
$.ajax({
type: "POST",
url: "index.php",
data: data_to_send,
success: function(msg){
$('.answer').html(msg);
}
});