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The purpose of the embedded script is to interpret the ZIP payload as binary data, extract it, and then display the extracted page with its resources. Initially, the script can use the `window.fetch()` method to read the HTML page in binary form and retrieve the ZIP payload. However, this API doesn't work in Chromium-based and WebKit-based browsers when the page is accessed from the local file system due to security restrictions. To circumvent this, the page is encoded in windows-1251, and binary data is directly retrieved from the Document Object Model (DOM) when using the "universal" self-extracting ZIP format. The choice to use windows-1251 encoding, rather than UTF-8, was made because, in UTF-8, any invalid bytes are converted into the `U+FFFD REPLACEMENT CHARACTER` making it impractical for this specific purpose due to a resulting significant data loss. With windows-1251 encoding, all bytes can be successfully recovered.
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-Regardless of page encoding, all instances of CR (Carriage Return) and CR+LF (Carriage Return Line Feed) bytes are replaced with LF (Line Feed) bytes when read from the DOM. As a consequence, additional data needs also to be incorporated into the page to restore this data loss. This task is accomplished by the `<sfz-extra-data>` tag, which contains both the necessary data and the offset specifying the start of the ZIP payload encoded in base64. The data in this tag is read by the embedded script before extracting the ZIP payload in order to restore CR (Carriage Return) and CR+LF (Carriage Return Line Feed) bytes. Finally, because the zip specification tolerates no more than 64KB of random data after the ZIP payload, this tag is positioned at the end or beginning of the HTML page (i.e. when it weighs more than 64KB).
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+Regardless of page encoding, all instances of CR (Carriage Return) and CR+LF (Carriage Return and Line Feed) bytes are replaced with LF (Line Feed) bytes when read from the DOM. As a consequence, additional data needs also to be incorporated into the page to restore this data loss. This task is accomplished by the `<sfz-extra-data>` tag, which contains both the necessary data and the offset specifying the start of the ZIP payload encoded in base64. The data in this tag is read by the embedded script before extracting the ZIP payload in order to restore CR (Carriage Return) and CR+LF (Carriage Return and Line Feed) bytes. Finally, because the zip specification tolerates no more than 64KB of random data after the ZIP payload, this tag is positioned at the end or beginning of the HTML page (i.e. when it weighs more than 64KB).
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Gildas