function toggle(layer,id){
var i = 0;
for(i = 0; document.getElementById( layer+'-'+i);i++) document.getElementById(layer+'-'+i).style.display = 'none';
	displayType = ( document.getElementById( layer+'-'+id ).style.display == 'none' ) ? 'block' : 'none';
    document.getElementById( layer+'-'+id ).style.display = displayType;
}