What are Unicode characters?

Unicode is an important universal character coding standard for interaction and display, which covers languages in the United States, Europe, the Middle East, Africa, India, Asia and the Pacific, as well as ancient Chinese and professional symbols. Unicode allows the exchange, processing and display of multilingual text and common professional and mathematical symbols. It hopes to solve multilingual computing, such as character standards in different countries, but not all modern or ancient Chinese can support it.

Unicode characters can be applied to all known encodings. Unicode is a new character code after ASCII. It defines a number and name for each symbol, specifies the character and its numerical value (code point), and the binary representation of the value. It defines a value of 16 with a hexadecimal number and a prefix (u), such as: U+00465438+. Please note, however, that versions before JavaScript 1.3 do not support Unicode encoding.

Compatibility of Unicode with ASCII and ISO

Unicode is compatible with ASCII characters and is supported by most programs. The pre-128 Unicode code has the same byte value as the ASCII code. Unicode characters from U+0020 to U+007E are equivalent to 0x20 to 0x7E of ASCII code. Unlike 7-bit ASCII, which supports Latin letters, Unicode sets an encoding value of 16 bits for each character, which allows tens of thousands of characters. For example, the Unicode version contains 38,885 characters. Can also be extended. For example, UTF- 16 allows 16 characters to be combined into one million or more characters, while UTF converts the encoding into real binary bits.

Unicode is fully compatible with the international standard ISO/IEC10646-1; 1993, a subset of ISO 10646, supports two octal numbers of ISO UCS-2 (Universal Character Set). JavaScript 1.3 support for Unicode means that you can use local characters and special scientific symbols in your program at will. Unicode provides a standard way to encode multilingual text, and because it is compatible with ASCII, you can also use ASCII characters at will.

Unicode escape sequence

You can use Unicode escape sequences in character text, which consists of six ASCII characters: \u plus a hexadecimal number with four values. For example: \u00A9 stands for copyright symbol. Each Unicode escape sequence in JavaScript is interpreted by a character. The following table shows commonly used special characters and their Unicode values.

Category Unicode Value Name Format Name

Blank \ u0009 tab

\u000B Vertical tab

\ u000C page break

\u0020 space

Line terminator value \u000A newline character

\u000D Enter.

Other Unicode escape sequence values \u000b backspace.

\u0009 Horizontal tab

\u0022 Double quotation marks "

\u0027 Single quotation marks'

\u005C backslash/

JavaScript uses Unicode escape sequences differently from Java. First, escape sequences are not interpreted as special characters in JavaScript. For example, the escape sequence of a line break in a string will not terminate the string until the function is interpreted, and JavaScript will ignore it if it is used in comments. In Java, if an escape sequence is used in a single comment line, it will be interpreted as a Unicode character. For string literals, the Java compiler will first interpret the escape sequence. For example, if you use a line break (\ u000A) in Java, it will terminate the string and cause an error in Java. Because line breaks are not allowed in string literals, you must use the \n symbol; In JavaScript, there is no difference between the two.

Display characters in Unicode

You can use Unicode to display characters or professional symbols in different languages, but this requires that the client can support Unicode, such as Netscape Navigator 4.x, and the client must also support Unicode fonts and operating platforms. For example, Windows 95 only supports partial Unicode. In addition, in order to input non-ASCII characters, you must have an input device that supports all Unicode characters. Standard extended keyboards can't do this, but we can use Unicode escape sequences to enter Unicode characters. If you need more information about Unicode, please refer to the Unicode Consortium website version 2.0.