May 20, 2023
Character encoding is the process of converting characters, such as letters, numbers, and symbols, into a digital representation that can be transmitted and understood by computers. In the context of the web, character encoding is an essential part of transmitting and displaying text in various languages and scripts.
When we type characters on a keyboard, they are represented in a form called a character set. A character set is a standard set of letters, numbers, and symbols that are used to represent text. In order to transmit this text over a network or store it in a file, these characters need to be encoded into a digital format that can be understood by computers. This is where character encoding comes in.
How Character Encoding Works
Character encoding works by mapping each character in a character set to a unique numeric value that can be represented in binary form. The most common character encoding standard used on the web is called ASCII (American Standard Code for Information Interchange), which maps each character to a 7-bit binary value. This allows for a total of 128 possible characters to be represented, including uppercase and lowercase letters, numbers, and various symbols.
However, the ASCII character set is limited to just the English language and a few other Western European languages. In order to support other languages and scripts, various other character encoding standards have been developed over time, such as ISO-8859, Unicode, and UTF-8.
Types of Character Encoding
ASCII (American Standard Code for Information Interchange)
ASCII is one of the oldest and most widely used character encoding standards. It uses 7-bit binary values to represent a total of 128 characters, including uppercase and lowercase letters, numbers, and various symbols. ASCII is limited to just the English language and a few other Western European languages.
The ISO-8859 standard is a series of 8-bit character encoding standards that were developed to support various languages and scripts. There are 16 different ISO-8859 standards, each of which supports a different set of languages and scripts. For example, ISO-8859-1 supports Western European languages, ISO-8859-2 supports Central European languages, and ISO-8859-5 supports Cyrillic languages.
Unicode is a character encoding standard that supports almost all of the world’s languages and scripts. It uses a unique numeric value for each character, which can be represented in binary form using variable-length encoding. Unicode currently supports over 143,000 characters, including characters from ancient scripts, emoji, and symbols.
UTF-8 is a variable-length character encoding standard that is based on Unicode. It uses between 1 and 4 bytes to represent each character, depending on the character’s value. UTF-8 is the most commonly used character encoding standard on the web, as it supports almost all of the world’s languages and scripts.
Choosing the Right Character Encoding
Choosing the right character encoding is critical to ensuring that text is transmitted and displayed correctly on different devices and in different languages. When a text file is created, it is important to select the appropriate character encoding based on the languages and scripts that will be used.
Most modern web browsers can automatically detect the character encoding of a web page, based on information included in the HTML or HTTP headers. However, it is still important to specify the character encoding explicitly, to ensure that text is displayed correctly on all devices.