How to perform encoding conversion in html

HTML encoding conversion: ASCII code, Unicode and UTF-8

HTML is a markup language used to create web pages. Its text contains not only visual characters, but also some Markup symbols that control text format, structure, and style. These markup symbols are parsed and rendered in the web browser, but in the background, these characters need to be correctly encoded and decoded to ensure their normal transmission and display. In this article, we will introduce the three commonly used encoding methods of HTML: ASCII, Unicode and UTF-8, and discuss how to convert them to each other.

1. ASCII code

ASCII (American Standard Code for Information Interchange, American Standard Code for Information Interchange) code is one of the earliest character encoding methods. It combines 128 commonly used characters. The characters and symbols are mapped to a 7-bit binary encoding. As shown in the figure below, the first column is the ASCII encoded character, the second column is the corresponding decimal value, and the third column is the binary code.

#ASCII encoding is a single-byte encoding that uses one byte (8 bits) to represent a character. With only 128 characters, the ASCII character set is relatively small and lacks support for multiple languages.

2. Unicode

Unicode is a global character set that contains characters and symbols in various languages, so that people who communicate on the Internet are no longer limited to a certain Instead, all characters including Latin alphabet, Chinese, Japanese, and Hebrew can be used. Unicode encoding can use different storage methods, including UTF-8, UTF-16, and UTF-32.

The Unicode character set contains more than 100,000 characters and symbols, so multiple bytes are needed to represent a character. Among them, UTF-8 encoding is a variable-length encoding method. It uses 1-4 bytes to represent a character, so that all characters in the Unicode character set can be represented in different ASCII codes, Latin-1 and other encoding methods. character. The first byte of UTF-8 encoding is used to indicate how many bytes are used to represent the character, and subsequent bytes start with 10.

The following table is a comparison table of the Chinese character "you" and the English character "A" under UTF-8 encoding:

##you11100110 10001101 10011000A01000001

Character	UTF-8 encoding

UTF-8 encoding conversion

In the actual programming process, we often need to convert character sets. Convert ASCII or Unicode-encoded characters to UTF-8-encoded characters, or convert UTF-8-encoded characters to ASCII or Unicode-encoded characters.

In Python, we can use the encode() and decode() methods to convert character sets. Among them, the encode() method converts the specified string into a byte string according to the specified encoding method, and the decode() method converts the specified byte string into a string according to the specified encoding method.

The following is an example of converting the Unicode-encoded string "Hello, World" to UTF-8 encoding, and then converting it back to Unicode encoding:

# 将Unicode编码的字符串转换为UTF-8编码
utf8_str = "你好，世界".encode('utf-8')
print(utf8_str)

# 将UTF-8编码的字符串转换为Unicode编码
unicode_str = utf8_str.decode('utf-8')
print(unicode_str)

The output result is:

b'\xe4\xbd\xa0\xe5\xa5\xbd\xef\xbc\x8c\xe4\xb8\x96\xe7\x95\x8c'
你好，世界

In this example, we first convert the Unicode-encoded string "Hello, World" into a UTF-8-encoded byte string using the encode() method, and then print it out. Next, we use the decode() method to convert this UTF-8 encoded byte string into a Unicode encoded string and print it out.

Conclusion

When writing HTML code, we need to ensure that the correct encoding is used to convert various characters and symbols into byte strings for transmission. In this article, we introduce three commonly used encoding methods: ASCII code, Unicode and UTF-8, and discuss the mutual conversion between them. In actual programming, we can use Python's built-in encode() and decode() methods to convert various character sets to better handle multilingual text processing.

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