[翻译]High Performance JavaScript(015)

第五章  Strings and Regular Expressions  字符串和正则表达式
    Practically all JavaScript programs are intimately tied to strings. For example, many applications use Ajax to fetch strings from a server, convert those strings into more easily usable JavaScript objects, and then generate strings of HTML from the data. A typical program deals with numerous tasks like these that require you to merge, split, rearrange, search, iterate over, and otherwise handle strings; and as web applications become more complex, progressively more of this processing is done in the browser.
    几乎所有JavaScript程序都与字符串操作紧密相连。例如，许多应用程序使用Ajax从服务器获取字符串，将这些字符串转换成更易用的JavaScript对象，然后从数据中生成HTML字符串。一个典型的程序需要处理若干这样的任务，合并，分解，重新排列，搜索，遍历，以及其他方法处理字符串。随着网页应用越来越复杂，越来越多的此类任务将在浏览器中完成。
    In JavaScript, regular expressions are essential for anything more than trivial string processing. A lot of this chapter is therefore dedicated to helping you understand how regular expression engines internally process your strings and teaching you how to write regular expressions that take advantage of this knowledge.
    在JavaScript中，正则表达式是必不可少的东西，它的重要性远超过琐碎的字符串处理。本章使用相当篇幅帮助您了解正则表达式引擎处理字符串的原理，并讲授如何利用这些知识书写正则表达式。
    Also in this chapter, you'll learn about the fastest cross-browser methods for concatenating and trimming strings, discover how to increase regex performance by reducing backtracking, and pick up plenty of other tips and tricks for efficiently processing strings and regular expressions.
    通过本章内容，您还将学到关于连接、修整字符串的最快的跨浏览器方法，探索如何通过减少回溯来提高正则表达式的性能，并挑选了一些关于高效处理字符串和正则表达式的技巧。
String Concatenation  字�