var actif = setInterval("timer()", 1000);
var time = 1; // temps en seconde

function timer() {
	if(time<=0) {
		document.getElementById('timer').innerHTML = "00:00";
		clearInterval(actif);
		
		showmodal("../ajout.php", 500);
	}
	else {
		var minutes = Math.floor(time/60);
		var secondes = Math.floor(time%60);
		if(minutes<10) minutes = "0"+minutes;
		if(secondes<10) secondes = "0"+secondes;
		var affichage = minutes+":"+secondes;
		
		document.getElementById('timer').innerHTML = affichage;
		time--;
	}
}