function show_accueil(){
		document.getElementById('survol_accueil').style.visibility = "visible";
		document.getElementById('survol_vente').style.visibility = "hidden";
		document.getElementById('survol_agence').style.visibility = "hidden";
		document.getElementById('survol_contact').style.visibility = "hidden";
}

function show_agence(){
		document.getElementById('survol_accueil').style.visibility = "hidden";
		document.getElementById('survol_vente').style.visibility = "hidden";
		document.getElementById('survol_agence').style.visibility = "visible";
		document.getElementById('survol_contact').style.visibility = "hidden";
}

function show_vente(){
		document.getElementById('survol_accueil').style.visibility = "hidden";
		document.getElementById('survol_vente').style.visibility = "visible";
		document.getElementById('survol_agence').style.visibility = "hidden";
		document.getElementById('survol_contact').style.visibility = "hidden";
}

function show_contact(){
		document.getElementById('survol_accueil').style.visibility = "hidden";
		document.getElementById('survol_vente').style.visibility = "hidden";
		document.getElementById('survol_agence').style.visibility = "hidden";
		document.getElementById('survol_contact').style.visibility = "visible";
}