getjson request fails, when i run in my remote hosting i not have problems, but when i run in localhost the request fails, what's wrong? i´m getting this error:
SyntaxError: Unexpected token < in JSON at position 0
CLIENT
$(document).ready(function() {
    var getdetails = function(id) {
        return $.getJSON("20.php", {
            id: "1"
        });
    } //END FUNCTION getdetails
    var searchData = function(user) {
        getdetails(user)
            .done(function(response) {
                if (response.success) {
                    $.each(response.data.users, function(key, value) {
                        $.each(value, function(userkey, uservalue) {});
                    });
                } else {
                    alert("Fail");
                }
            })
            .fail(function(jqXHR, textStatus, errorThrown) {
                alert(errorThrown);
            });
    }; //END FUNCTION searchData
    searchData("1");
    var socket = io();
    socket.emit('room', prompt('suscribe to channel...'));
});
SERVER
var app = require('express')();
var express = require('express');
var http = require('http').Server(app);
var io = require('socket.io')(http);
app.use(express.static('./public'));
var users = [];
var nicks = new Array();
app.get('/', function(req, res) {
    res.sendFile(__dirname + '/index.html');
});
io.sockets.on('connection', function(socket) {
    socket.on('room', function(room) {
socket.join(room);
    });
});
http.listen(3000, function() {
    console.log('listening on *:3000');
});

