how to have 1st person controls with mouse for camera look?

var m_plock = require("pointerlock");
var m_cons = require("constraints");
var m_scs = require("scenes");
var m_main  = require("main");

function enable_firstperson_controls() {
    var character = m_scs.get_first_character();
    var camera = m_scs.get_active_camera();

    // make camera follow the character with offset [0, 0.5, 0]
    m_cons.append_stiff_trans(camera, character, [0, 0.5, 0]);

    // enable rotation with mouse
    var canvas_elem = m_main.get_canvas_elem();
    canvas_elem.addEventListener("mouseup", function(e) {
        m_plock.request_pointerlock(canvas_elem);
    }, false);
}