if(document.images)
      {
         off    = new Array();
         off[0] = new Image(); off[0].src = "images/logo_sdm.gif";
         
         on     = new Array();
         on[0]  = new Image(); on[0].src  = "images/logo_sdm_ov.gif";
      }

      function switchImg(row,s)
      {
         if(!document.images)
            return;
         document.images['r'+row].src = (s==1)?on[row].src:off[row].src;
      }
	  
function changeActive(idlayer1,idlayer2,idlayer3){

	document.getElementById(idlayer1).className = 'actif';
	document.getElementById(idlayer2).className = '';
	document.getElementById(idlayer3).className = '';
}