摘要： readyState Status CodeStatus of the XMLHttpRequest Object(0) UNINITIALIZED 未初始化The object has been created but not initialized. (The open method has not been called.)（XMLHttpRequest）对象已经创建，但尚未初始化（还没有调用open方法）。(1) LOADING 载入The object has been created, but the send method has not been called.（XMLHttp 阅读全文