Chronomètre

stopwatch.js

/*
id : String - l'identifiant d'un élément HTML (un div ou un span par exemple)
seconds : Int - Nombre de secondes
*/
function Stopwatch(id, seconds) {
	var self = this;

	this.seconds = seconds;
	this.el = document.getElementById(id);
	this.h = this.m = this.s = 0;

	this.timer = setInterval(function() {
		self.tick();
	}, 1000);

	this.tick();
};

Stopwatch.prototype.tick = function() {
	if (this.seconds < 0) {
		clearInterval(this.timer);
	} else {
		this.h = Math.floor(this.seconds / 3600);
		this.m = Math.floor((this.seconds - (this.h * 3600)) / 60);
		this.s = Math.floor(this.seconds % 60);

		this.show();

		this.seconds--;
	}
};

Stopwatch.prototype.show = function() {
	var hh = this.h < 10 ? '0' + this.h : this.h;
	var mm = this.m < 10 ? '0' + this.m : this.m;
	var ss = this.s < 10 ? '0' + this.s : this.s;

	this.el.innerHTML = hh + ':' + mm + ':' + ss;
};

// Utilisation :
new Stopwatch('stats', 2);