[翻译]High Performance JavaScript(024)
Data Format Conclusions 数据格式总结
Favor lightweight formats in general; the best are JSON and a character-delimited custom format. If the data set is large and parse time becomes an issue, use one of these two techniques:
总的来说越轻量级的格式越好，最好是JSON和字符分隔的自定义格式。如果数据集很大或者解析时间成问题，那么就使用这两种格式之一：
• JSON-P data, fetched using dynamic script tag insertion. This treats the data as executable JavaScript, not a string, and allows for extremely fast parsing. This can be used across domains, but shouldn't be used with sensitive data.
JSON-P数据，用动态脚本标签插入法获取。它将数据视为可运行的JavaScript而不是字符串，解析速度极快。它能够跨域使用，但不应涉及敏感数据。
• A character-delimited custom format, fetched using either XHR or dynamic script tag insertion and parsed using split(). This technique parses extremely large datasets slightly faster than the JSON-P technique, and generally has a smaller file size.
字符分隔的自定义格式，使用XHR或动态脚本标签插入技术提取，使用split()解析。此技术在解析非常大数据集时比JSON-P技术略快，而且通常文件尺寸更小。
The following table and Figure 7-1 show all of the performance numbers again (in order from slowest to fastest), so that you can compare each of the formats in one place. HTML is excluded, since it isn't directly comparable to the other formats.
下表和图7-1再次显示了所有方法的性能数据（按照从慢到快的顺序），你可以在此比较每种格式的优劣。HTML未包括，因为它与其他格式不能直接比较。
Figure 7-1. A comparison of data format download and parse times
图7-1 各种数据格式下载和解析的时间
Keep in mind that these numbers are from a single test run in a single browser. The results should be used as general indicators of performance, not as hard numbers. You can run these tests yourself at http://techfoolery.com/formats/.
请注意，这些�
相关文档：
本文主要是出于有朋友使用我原来写的autocomplete的JS控件。当数据量大的时候，会出现效率极其慢的情况，我在这段时间做出的一些测试也及一些经验，与大家分享，如果有错的地方，还请指出。
经过测试，我们会发现如下的情况或者说的结论，如果您的测试结果与我的不符，请说明原因，以便相互学习。
1）当一个较大的HTML字� ......
Repaints and Reflows 重绘和重排版
Once the browser has downloaded all the components of a page—HTML markup, JavaScript, CSS, images—it parses through the files and creates two internal data structures:
当浏览器下载完所有页面HTML标记，JavaScri ......
Conditionals 条件表达式
Similar in nature to loops, conditionals determine how execution flows through JavaScript. The traditional argument of whether to use if-else statements or a switch statement applies to JavaScript just as it does to other languages. Since different b ......
Recursion Patterns 递归模式
When you run into a call stack size limit, your first step should be to identify any instances of recursion in the code. To that end, there are two recursive patterns to be aware of. The first is the straightforward recursive pattern represented ......
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.
......
