var mc = 1;

window.onload = function(){
	document.getElementById("media-prec").onclick = function(){
		if(mc > 1){
			document.getElementById("media-" + mc).style.display = "none";
			mc--;
			document.getElementById("media-" + mc).style.display = "block";
		}
	}
	document.getElementById("media-suiv").onclick = function(){
		if(mc < 3){
			document.getElementById("media-"+mc).style.display = "none";
			mc++;
			document.getElementById("media-"+mc).style.display = "block";
		}
	}
}