function MM_showHideLayers() { //v3.0
  var i,p,v,obj,args=MM_showHideLayers.arguments;
  for (i=0; i<(args.length-2); i+=3) if ((obj=MM_findObj(args[i]))!=null) { v=args[i+2];
    if (obj.style) { obj=obj.style; v=(v=='show')?'visible':(v='hide')?'hidden':v; }
    obj.visibility=v; }
}

function MM_HideLayers() { 
MM_showHideLayers('ev1','','hide') ; MM_showHideLayers('ev2','','hide') ; MM_showHideLayers('ev3','','hide') ; MM_showHideLayers('ev4','','hide') ; MM_showHideLayers('ev5','','hide') ; MM_showHideLayers('ev6','','hide') ;  MM_showHideLayers('ev7','','hide') ; MM_showHideLayers('ev8','','hide') ; MM_showHideLayers('ev9','','hide') ; MM_showHideLayers('ev10','','hide') ; MM_showHideLayers('ev11','','hide') ; MM_showHideLayers('ev12','','hide') ;
MM_showHideLayers('ev13','','hide') ; MM_showHideLayers('ev14','','hide') ; MM_showHideLayers('ev15','','hide') ; MM_showHideLayers('ev16','','hide') ; MM_showHideLayers('ev17','','hide') ; MM_showHideLayers('ev18','','hide') ; MM_showHideLayers('ev19','','hide') ; MM_showHideLayers('ev20','','hide') ;
}