HTML5 - Character Encodings

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A character encoding is a method of converting bytes into characters. To validate or display an HTML document, a program must choose a character encoding. HTML 5 authors have three means of setting the character encoding −

HTTP Content-Type Header

If you are writing cgi or similar program then you would use HTTP Content-Type header to set any character encoding.

Following is the simple example −

print "Content-Type: text/html; charset=utf-8\r\n";

The <meta> element

You can use a <meta> element with a charset attribute that specifies the encoding within the first 512 bytes of the HTML5 document.

Following is the simplified example −

<meta charset="UTF-8">

Above syntax replaces the need for <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> although that syntax is still allowed.

Unicode Byte Order Mark (BOM)

A byte order mark (BOM) consists of the character code U+FEFF at the beginning of a data stream, where it can be used as a signature defining the byte order and encoding form, primarily of unmarked plaintext files.

Many Windows programs (including Windows Notepad) add the bytes 0xEF, 0xBB, 0xBF at the start of any document saved as UTF-8. This is the UTF-8 encoding of the Unicode byte order mark (BOM), and is commonly referred to as a UTF-8 BOM even though it is not relevant to byte order.

For HTML5 document, you can use a Unicode Byte Order Mark (BOM) character at the start of the file. This character provides a signature for the encoding used.