text: // arange
  function arange (start, stop, step){
        step = step || 1;
        var arr = [];
        for (var i=start;i<stop;i+=step){
           arr.push(i);
        }
        return arr;
  };
  
  /****
  use:
  
  arr = arange(0,10,1);
  
  console.log(arr)
  
  //--> [0,1,2,3,4,5,6,7,8,9]
  
  ****/
  