var a = {
    init: function(){
        return 'a';
    }
},
b = a;

if(b['load'] == undefined) b['load'] = {};
b = b['load'];

console.log(a);

var a = {
    init: function(){
        return 'a';
    }
},
//上面定义了一个a
b = a;//将a赋予b。
//你想明白的就是下面这句了
//b['load'] == undefined如果b中不存在load，那么b['load']={};你上面的是建了一个空对象。我这里加多了个属性a:'1'
if(b['load'] == undefined) b['load'] = {a:'1'};
b = b['load'];//又把b['load']指回b了

alert(b.a);//因为b['load'] = {a:'1'};所以，这里弹出'1'

------解决方案--------------------

JScript code
<script type="text/javascript">
    var a = {};
    var b = a;//相互鬼上身附体
    a['c']={};
    console.log(b); //Object { c={...}}
    b['a']={};
    console.log(a); //Object { c={...}, a={...}}
</script>