json对象合并的方法

var a ={"a":"1","b":"2"}
var b ={"c":"3","d":"4","e":"5"}

想得到结果：

var c ={"a":"1","b":"2","c":"3","d":"4","e":"5"}


怎么弄？？

==================

<script>
function extend(des, src, override){
    if(src instanceof Array){
        for(var i = 0, len = src.length; i < len; i++)
             extend(des, src[i], override);
    }
    for( var i in src){
        if(override || !(i in des)){
            des[i] = src[i];
        }
    }
    return des;
}
var a ={"a":"1","b":"2"}
var b ={"c":"3","d":"4","e":"5"}
var c = extend({}, [a,b]);
alert(c.a);
</script>