function showMenu(variable){
	var element = document.getElementById(variable);
	
	hideAllMenus();
	element.style.display = "block";
}

function hideMenu(variable){
	var element = document.getElementById(variable);
	
	element.style.display = "none";
}

function hideAllMenus(){
	if(document.getElementById('dhtmlcomprendre')) hideMenu('dhtmlcomprendre');
	if(document.getElementById('dhtmlpratique')) hideMenu('dhtmlpratique');
}