no byte order mark. While the encoding default for HTML pages served as XML is required to be UTF-8, the encoding default for a regular Web page (that is: for HTML pages serialized as text/html) varies depending on the localization of the browser. For a system set up mainly for Western European languages, it will generally be Windows-1252. For Cyrillic alphabet locales, the default is typically Windows-1251. For a browser from a location where legacy multi-byte character encodings are prevalent, some form of auto-detection is likely to be applied. Encoding trends Because of the legacy of 8-bit text representations in programming languages and operating systems and the desire to avoid burdening users with the need to understand the nuances of encoding, many text editors used by HTML authors are unable or unwilling to offer a choice of encodings when saving files to disk and often do not even allow input of characters beyond a very limited range. Consequently, many HTML authors are unaware of encoding issues and may not have any idea what encoding their documents actually use. Misunderstandings, such as the belief that the encoding declaration affects a change in the actual encoding (whereas it is actually just a label that could be inaccurate), is also a reason for this editor attitude. Another factor contributing in the same direction, is the arrival of UTF-8 which greatly diminishes the need for other encodings, and thus modern editors tends to default, as recommended by the HTML5 specification, to UTF-8. Byte order mark/Unicode sniffing For both serializations of HTML (content-type "text/html" and content/type "application/xhtml+xml"), the byte order mark (BOM) is an effective way to transmit encoding information within an HTML document. For UTF-8, the BOM is optional, while it is a must for the UTF-16 and the UTF-32 encodings. (Note: UTF-16 and UTF-32 without the BOM are formally known under different names, they are different encodings, and thus needs some form of encoding declaration – see UTF-16BE, UTF-16LE, UTF-32LE and UTF-32BE.) The use of the BOM character (U+FEFF) means that the encoding automatically declares itself to any processing application. Processing applications need only look for an initial 0x0000FEFF, 0xFEFF or 0xEFBBBF in the byte stream to identify the document as UTF-32, UTF-16 or UTF-8 encoded respectively. No additional metadata mechanisms are required for these encodings since the byte-order mark includes all of the information necessary for processing applications. In most circumstances, the