[rgl]

function example(arr, type) {
  if( type == 'asc' ) {
    var start = 0, end = arr.length, step = 1;
  } else {
    start = arr.length; end = -1; step = -1;
  }
  for (var x = start; x != end; x += step ) {
    alert(arr[x]);
  }
}