[翻译]High Performance JavaScript(023)
Data Formats 数据格式
When considering data transmission techniques, you must take into account several factors: feature set, compatibility, performance, and direction (to or from the server). When considering data formats, the only scale you need for comparison is speed.
在考虑数据传输技术时，你必须考虑这些因素：功能集，兼容性，性能，和方向（发给服务器或者从服务器接收）。在考虑数据格式时，唯一需要比较的尺度的就是速度。
There isn't one data format that will always be better than the others. Depending on what data is being transferred and its intended use on the page, one might be faster to download, while another might be faster to parse. In this section, we create a widget for searching among users and implement it using each of the four major categories of data formats. This will require us to format a list of users on the server, pass it back to the browser, parse that list into a native JavaScript data structure, and search it for a given string. Each of the data formats will be compared based on the file size of the list, the speed of parsing it, and the ease with which it's formed on the server.
没有哪种数据格式会始终比其他格式更好。根据传送什么数据、用于页面上什么目的，某种格式可能下载更快，另一种格式可能解析更快。在本节中，我们创建了一个窗口小部件用于搜索用户信息并用四种主流的数据格式实现它。这要求我们在服务器端格式化一个用户列表，将它返回给浏览器，将列表解析成JavaScript数据格式，并搜索特定的字符串。每种数据格式将比较列表的文件大小，解析速度，和服务器上构造它们的难易程度。
XML
When Ajax first became popular, XML was the data format of choice. It had many things going for it: extreme interoperability (with excellent support on both the server side and the client side), strict formatting, and easy validation. JSON hadn't been formalized yet as an interchange format, and almost every language used on servers had a library available for working with XML.
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相关文档：
＜script language="javaScript"＞
function closeWindow()
{
window.opener = null;
window.open(' ', '_self', ' ');
window.close();
}
＜/script＞
＜input type='button' value='关闭窗口' onClick="closeWindow()"＞
或
＜input type="button" value="� ......
玩PHP、Delphi、Java基本上都有对象，习惯这种思路后上手任何语言都想靠OO思路，这绝不是在赶时髦，而是把相关代码进行内聚的确可以体会到维护的方便！
在JavaScript中如何创建对象？
JavaScript是基于对象的！它也是以Object为根类，其它类继承之。在根类提供了几个方法。供继承类使用！
以下是创建对象的例子：
funct ......
AJAX (异步 JavaScript 和 XML) 是个新产生的术语,专为描述JavaScript的两项强大性能.这两项性
能在多年来一直被网络开发者所忽略,直到最近Gmail, Google suggest和google Maps的横空出世才使人
们开始意识到其重要性.
这两项被忽视的性能是:
* 无需重新装载整个页面便能向服务器发送请求.
* 对XML文档的解析和处理．
......
Yielding with Timers 用定时器让出时间片
Despite your best efforts, there will be times when a JavaScript task cannot be completed in 100 milliseconds or less because of its complexity. In these cases, it's ideal to yield control of the UI thread so that UI updates may occur ......
