Merge as it should be ( == $.extend(true, {}, ...))

merge.js

function myextend(/* args */){
var o = {}
,  args = Array.prototype.slice.call(arguments)
,  obj = args.shift()
,  src = args.shift();

  for (var p in src){
    if (src.hasOwnProperty(p)){
      if (hasOwn.call(obj,p) && typeof obj[p] === 'object' && obj[p] !== null) {
        o[p] = myextend(obj[p],src[p]);
      }
      else {
        o[p] = src[p];
      }
    }
  }

  return args.length > 0 ? myextend.apply(null, [o].concat(args)) : o;
}

/* 
var a = {};
var b = {a:'Hello', b:{}};
var c = {a:'Bye', b:{f:{d:2}}, c:1};

var r = myextend(a, b, c);

alert(JSON.stringify(r,null,0)); //{"a":"Bye","b":{"f":{"d":2}},"c":1}
*/