gistfile1.js

function p (s, b, e, d) {
  var c = null;
  var i = 0;
  var n = 0;
  var r = [];
  var x = 0;
  var y = 0;

  while (null != (c = s[i++])) {
    // got first brace
    if (b == c && 0 == x) {
      x = 1;
      r[n] = ""; // empty string for token
      continue;
    }

    // found token delimiter
    // and setting token `y' flag
    // to 1
    if (1 == x && d == c) {
      y = 1;
      continue;
    }

    // in brace and
    // found first token
    // after brace
    if (1 == x && 0 == y && d != c) {
      r[n] += c;
      continue;
    }

    // found end brace
    // and first brace found
    // and delimiter set
    if (e == c && 1 == x && 1 == y) {
      n++;
      x = 0;
      y = 0;
    }
  }

  return r;
}

console.log(p(
    "[foo; after] bla hello [bar; after] biz baz omfg [yo; balha sa sas ah] dfd"
  , '['
  , ']'
  , ';'
));