js对象深度拷贝

js对象深度拷贝，断开引用，避免出现引用问题

function deepCopy(obj){
    if(typeof obj != 'object'){
        return obj;
    }
    var newobj = {};
    for ( var attr in obj) {
        newobj[attr] = deepCopy(obj[attr]);
    }
    return newobj;
}