function afficher(thingId)
{
var targetElement;
targetElement = document.getElementById(thingId) ;
if (targetElement.style.display == "none")
{
targetElement.style.display = "" ;
document.getElementById("sf" + thingId).innerHTML = '<img src="./images/moins.gif" />';
} else {
targetElement.style.display = "none" ;
document.getElementById("sf" + thingId).innerHTML = '<img src="./images/plus.gif" />';
}
}