Why do you use timeouts for this simple task? You can just get time of mousedown, time of mouseup and calculate difference of them. Anyway, timer resolution in browsers is less than 1ms. Read this article of Nickolas Zakas to get more info about time resolution.
Code is:
var Game = cc.Layer.extend({
init: function () {
var holdStart = null,
holdTime = null;
this.canvas.addEventListener('mousedown', function(evt) {
holdStart = Date.now()
});
this.canvas.addEventListener('mouseup', function(evt) {
holdTime = Date.now() - holdStart;
// now in holdTime you have time in milliseconds
});
}