function range (low, high, step) {
  // http://kevin.vanzonneveld.net
  // +   original by: Waldo Malqui Silva
  // *     example 1: range ( 0, 12 );
  // *     returns 1: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
  // *     example 2: range( 0, 100, 10 );
  // *     returns 2: [0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
  // *     example 3: range( 'a', 'i' );
  // *     returns 3: ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i']
  // *     example 4: range( 'c', 'a' );
  // *     returns 4: ['c', 'b', 'a']
  var matrix = [];
  var inival, endval, plus;
  var walker = step || 1;
  var chars = false;

  if (!isNaN(low) && !isNaN(high)) {
    inival = low;
    endval = high;
  } else if (isNaN(low) && isNaN(high)) {
    chars = true;
    inival = low.charCodeAt(0);
    endval = high.charCodeAt(0);
  } else {
    inival = (isNaN(low) ? 0 : low);
    endval = (isNaN(high) ? 0 : high);
  }

  plus = ((inival > endval) ? false : true);
  if (plus) {
    while (inival <= endval) {
      matrix.push(((chars) ? String.fromCharCode(inival) : inival));
      inival += walker;
    }
  } else {
    while (inival >= endval) {
      matrix.push(((chars) ? String.fromCharCode(inival) : inival));
      inival -= walker;
    }
  }

  return matrix;
}

range ( 0, 12 );

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

range( 0, 100, 10 );

[0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100]

range( 'a', 'i' );

['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i']