function survolLangue(target){
	var cible = document.getElementById(target);
	var apparition = new OpacityTween(cible,Tween.regularEaseIn, 50, 100, 0.5);
	apparition.start();
}
function deSurvolLangue(target){
	var cible = document.getElementById(target);
	var disparition = new OpacityTween(cible,Tween.regularEaseIn, 100, 50, 0.5);
	disparition.start();
}