var extend = function(){

  function isFunction(fn){ return typeof(fn) === "function" && fn.constructor === Function }
  function isArray(ar){ return ar instanceof Array }
  function isPlainObject(obj){ return typeof o == 'object' && o.constructor == Object }

  var options, name, src, copy, copyIsArray, clone, target = arguments[0] || {}, i = 1, length = arguments.length, deep = false;
  if(typeof target === "boolean"){
    deep = target;
    target = arguments[i] || {};
    i++;
  }
  if(typeof target !== "object" && !isFunction(target)) target = {};
  if(i === length){
    target = this;
    i--;
  }
  for(; i < length; i++){
    if((options = arguments[i]) != null){
      for(name in options){
        src  = target[name];
        copy = options[name];
        if(target === copy) continue;

        if(deep && copy &&(isPlainObject(copy) ||(copyIsArray = isArray(copy)))){
          if(!copyIsArray){
            copyIsArray = false;
            clone = src && isArray(src) ? src : [];
          }
          else clone = src && isPlainObject(src) ? src : {};

          target[name] = extend(deep, clone, copy);
        }
	else if(copy !== undefined) target[name] = copy;
      }
    }
  }

  return target;
};