closest2.js

String.prototype.closest2 = function(find, pos) {
  var cur = 0;
  
  while (cur <= this.length) {
    if (pos + cur <= this.length) var is = this.substr(pos + cur, find.length);
    if (pos - cur > 0) var it = this.substr(pos - cur, find.length);
    
    if (is == find) return pos + cur;
    if (it == find) return pos - cur;
    
    cur++;
  }
  
  return -1;
};