JavaScript authoritative guide-lexical structure

Widely used, all browsers (desktop, mobile, screen, etc.) are equipped with the appropriate JavaScript parser.

Three skills: JavaScript, HTML, CSS.

JavaScript has long been beyond the scope of its "scripting language" itself and has become a programming language that combines robustness/efficiency and versatility.

The lexical structure of a programming language is a set of basic rules that describe how to use the language to write programs. As the basis of the syntax, it provides rules such as what the variable name is, how to write the comment, and how the program statements are split.

1. Character Set

JavaScript programs are written in the Unicode character set. Unicode is a superset of ASCII and Latin-l, and holds almost all the re-used languages on Earth. ECMAScript 3 requires that the implementation of JS must support Unicode2.1 and subsequent versions, and ECMASCRIPT5 requires support for UNIOCDE 3 and later versions.

Http://www.ruanyifeng.com/blog/2014/12/unicode.html

1.1. Case-sensitive

JS is a case-sensitive language. In other words, keywords, variables, function names, and all identifiers must be in a consistent case.

Note: HTML is case-insensitive, XHTML-differentiated.

For example, when you set an event handler in HTML, the OnClick property can be written as an onclick, but in the JS code or in an XHTML document, you must use the lower-case onclick.

1.2. Spaces, newline characters, format control characters

JS ignores spaces between the identities in the program. In most cases, JS also ignores line breaks. Because you can freely use spaces and line breaks in your code, you can make the code more readable by using neat, consistent indentation to form a unified coding style.

Characters in JavaScript that represent spaces: http://blog.csdn.net/sells2012/article/details/17509077

1.3.Unicode Escape Sequences

JavaScript authoritative guide-lexical structure