function $(eX){
  return document.getElementById(eX);
}

var largeur = 500;
var hauteur = 80;
//var lphoto = 120;
//var nbphoto = 16;
var sens = -1;
var ltotal = (nbphoto-1) * lphoto;
var photoLeft = 0;
var newLeft = 0;
var timer= 0;
	
function slide(largeur){
	if (sens < 0){
		for (var j=1;j<=nbphoto;j++){
			photoLeft = $('pub'+j).style.left;
			newLeft = Number(photoLeft.slice(0,-2)) + sens;
			if ( newLeft < (-lphoto)) {
				$('pub'+j).style.left = ltotal +'px';
			}else {
				$('pub'+j).style.left = newLeft +'px';
			}
		}
	}
	else if(sens > 0)  {
		for (var j=1;j<=nbphoto;j++){
			photoLeft = $('pub'+j).style.left;
			newLeft = Number(photoLeft.slice(0,-2)) + sens;
			if ( newLeft > ltotal) {
				$('pub'+j).style.left = -lphoto +'px';
			}else {
				$('pub'+j).style.left = newLeft +'px';
			}
		}
	}
}

function stopSlide(){
	clearInterval(timer)
	}

function slidePub(){
	largeur = $('bloc-image-defil').offsetWidth -2;
	$('gallery').style.width=largeur +'px';
	$('gallery').style.height=hauteur +'px';

	// on place les images
	for (var i=1;i<=nbphoto;i++){
		$('pub'+i).style.left = (i-1) * lphoto +'px';
		}	
	timer = setInterval(slide, 20);
	}

function change(lesens){
	sens = lesens;
	}