function change_z(zone, nr){
var pic=document.getElementById('divim'+nr);
var vieuxind=pic.style.zIndex
var act=document.getElementById('actuel')

for (i=1; i<=13; i++){
    re_z=document.getElementById('divim'+i);
    re_z.style.zIndex= 51-i
   }

act.coords=zone.coords
act.alt=zone.alt
act.href=zone.href
act.title=zone.title
pic.style.zIndex=100;

act.onmouseout=function(){pic.style.zIndex=vieuxind
                          act.alt=''
                          act.href=''
                          act.title=''
                          act.coords="1,1,1,2,2,2,2,1"
                         }
}