how does mootools make periodical() work the same in all browsers?

If you use setInterval with some code, the speed is different in different browsers. But with if i use the periodical() from mootools the speed is almost exactly the same, how does it do that? can someone show 开发者_StackOverflow社区me an example and explain?

Looks like mootools (as of version 1.3.2) just calls through to setInterval, so it should behave the same:

periodical: function(periodical, bind, args){
    return setInterval(this.pass((args == null ? [] : args), bind), periodical);
}