JavaScript is case sensitive, (HTML is case-insensitive, XHTML is case-sensitive)JavaScript ignores spaces between identities in programs, and in most cases JavaScript ignores line breaks The Unicode escape sequences are prefixed with \u followed by 4 hexadecimal digits. //Line comment;/* cross-line comment */JavaScript identifier must start with a letter, underscore (_), or dollar ($). Subsequent characters can be letters, numbers, underscores, or dollar characters (numbers are not allowed to appear as first characters, so that JavaScript can easily divide identifiers and numbers). There can be no line breaks between return, break, and continue and subsequent expressions (line wrapping then JavaScript automatically adds the end of the first line). the "+ +" and "--" operators should be on the same line as the suffix expression, otherwise the end of the line will fill the semicolon, and "+ +" or "--" will be parsed with the prefix operator for the next line of code. For example:x+ +y This code will parse to "x;++y" instead of "x++;y".
JavaScript Basics-Lexical structure
