JavaScript 权威指南（原书第7版）

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3.2 节介绍了 JavaScript 数值字面量的语法。3.3 节介绍了字符串字面量的语法。3.3.5 节

介绍了正则表达式字面量的语法，另外 11.3 节还会详细介绍。

JavaScript 的一些保留字也是主表达式：

4.1 Primary Expressions

The simplest expressions, known as primary expressions, are those that stand alone—

they do not include any simpler expressions. Primary expressions in JavaScript are

constant or literal values, certain language keywords, and variable references.

Literals are constant values that are embedded directly in your program. They look

like these:

1.23 // A number literal

"hello" // A string literal

/pattern/ // A regular expression literal

JavaScript syntax for number literals was covered in §3.2. String literals were ...