The code that sends the string looks like this, is it a json response perhaps?
$.getJSON(loadUrl, parameters, function (response) {
callback(response.data);
})
Does this mean that the response indeed is json? See below screenshot for the actual response given (when using alert(data)):

EDIT:
I think that the returned data is indeed json. This is what the console looks like when printing the data returend:

EDIT2:
The response was indeed json. I looped it like below:
$(data).each(function(index, element){
$('#scores').append('<tr><td> '+element[0]+' </td> <td> '+element[1]+' </td></tr>');
})