[翻译]High Performance JavaScript(028)
JavaScript Minification JavaScript紧凑
JavaScript minification is the process by which a JavaScript file is stripped of everything that does not contribute to its execution. This includes comments and unnecessary whitespace. The process typically reduces the file size by half, resulting in faster downloads, and encourages programmers to write better, more extensive inline documentation.
JavaScript紧凑指的是剔除一个JavaScript文件中一切运行无关内容的过程。包括注释和不必要的空格。该处理通常可将文件尺寸缩减到一半，其结果是下载速度更快，并鼓励程序员写出更好，更详细的内联文档。
JSMin (http://www.crockford.com/javascript/jsmin.html), developed by Douglas Crockford, remained the standard in JavaScript minification for a long time. However, as web applications kept growing in size and complexity, many felt it was time to push JavaScript minification a step further. This is the main reason behind the development of the YUI Compressor (http://developer.yahoo.com/yui/compressor/), a tool that performs all kinds of smart operations in order to offer a higher level of compaction than other tools in a completely safe way. In addition to stripping comments and unnecessary whitespace, the YUI Compressor offers the following features:
JSMin（http://www.crockford.com/javascript/jsmin.html），由Douglas Crockford开发，它保持了JavaScript紧凑标准很长一段时间。然而随着网络应用程序在规模和复杂性上不断增长，许多人认为JavaScript紧凑应当再向前推进一步。这是开发YUI压缩器的主要原因（http://developer.yahoo.com/yui/compressor/）它提供了所有类型的智能操作，为了提供比其它工具更高级的紧凑操作并且以完全安全的方法实现。除了剔除注释和不必要的空格，YUI压缩器还提供以下功能：
• Replacement of local variable names with shorter (one-, two-, or three-character) variable names, picked to optimize gzip compression downstream
将局部变量名替换以更短的形式（1个，2个，或3个字符），以优化后续的gzip压缩工作
• Rep
相关文档：
常规的方法是将年月日取出，然后分别判断范围，然后就判断闰年2月的天数
可以通过new Date(string)的构造，比较年月日字符是否发生变化判断。
function CheckDate(text) {
if (!text) return false;
text = text.replace(/[\/-]0?/g, "/");
if (!text.match(/^\d{4}\/\d{1,2}\/\d{1,2}$/)) return true;
......
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.
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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，� ......
第九章
Building and Deploying High-Performance JavaScript Applications
创建并部署高性能JavaScript应用程序
According to a 2007 study by Yahoo!'s Exceptional Performance team, 40%–60% of Yahoo!'s users have an empty cache experience, and about 20% of all page views are done ......
