range.js

var range = function(start, end, mult){
  if (end == undefined) {
    end = start;
    if (end < 0) {
      start = end;
      end = -1;
    } else if (end > 0) start = 1;
    else start = 0;
  }
  if (mult == undefined) mult = 1;
  else if (mult < 0) {
    var t = start;
    start = end;
    end = t;
    mult = -mult;
  } else if (mult == 0) return [];
  var sign = function(x) {
    if(x < 0) return -1;
    else return 1;
  }
  var r = [];
  var incr = sign(end-start) * mult;
  for (var i = start;!((i-incr <= end && end < i)||(i < end && end <= i-incr));i+=incr) r.push(i)
  return r;
}