counterstring.js

function counterstring(length) {
  var curNum = length;
  var outLen = 0;
  var numbers = [];
  var curStr;
  while (outLen < length) {
    curStr = curNum.toString() + "*";
    curNum -= curStr.length;

    if (outLen + curStr.length <= length) {
      numbers.push(curStr);
      outLen += curStr.length;
    }
    else {
      numbers.push("*");
      break;
    }
  }
  return numbers.reverse().join("");
}