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The data URI scheme is a uniform resource identifier (URI) scheme that provides a way to include data in-line in web pages as if they were external resources. It is a form of file literal or here document. This technique allows normally separate elements such as images and style sheets to be fetched in a single Hypertext Transfer Protocol (HTTP) request, which may be more efficient than multiple HTTP requests. Data URIs are sometimes referred to incorrectly as "data URLs". , data URIs are fully supported by most major browsers, and partially supported in Internet Explorer and Microsoft Edge. ==Syntax== The syntax of data URIs was defined in Request for Comments (RFC) 2397, published in August 1998, and follows the URI scheme syntax. A data URI consists of: data:(type>'' )(set>'' )(),''<data>'' * The scheme, data. It is followed by a colon (:).* An optional media type. If one is not specified, the media type of the data URI is assumed to be text/plain.* An optional character set parameter, separated from the preceding part by a semicolon ( ;) . A character set parameter comprises the label charset, an equals sign (=), and a value from the IANA list of official character set names. If this parameter is not present, the character set of the content is assumed to be US-ASCII (ASCII).* The optional base64 extension base64, separated from the preceding part by a semicolon. When present, this indicates that the data content of the URI is binary data, encoded in ASCII format using the Base64 scheme for binary-to-text encoding. Data URIs encoded in Base64 may contain whitespace for human readability.* The data, separated from the preceding part by a comma ( ,). The data is a sequence of octets represented as characters. Permitted characters within a data URI are the ASCII characters for the lowercase and uppercase letters of the modern English alphabet, and the Arabic numerals. Octets represented by any other character must be percent-encoded, as in %26 for an ampersand (&).抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Data URI scheme」の詳細全文を読む スポンサード リンク
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