The Old NetISSUE #23 of 60

when xhtml still matters · e-readers · epub

Pixel PeteVSQuirks Mode

Pixel Pete saysXHTML still matters where strict XML is required — EPUB e-books and XML toolchains.

The discipline lives on in specific niches. EPUB (e-book format) content documents are XHTML, so e-reader tooling can parse them strictly. Any pipeline that processes pages as XML (some CMS exports, archival systems, MathML/SVG-heavy documents) benefits from XHTML's guarantees. If your output feeds an XML parser, XHTML is the right call.

Power-ups you unlock

EPUB content documents are XHTML
XML toolchains need the strict guarantees
Archival & MathML/SVG-heavy docs benefit
Use XHTML when output feeds an XML parser

Quirks Mode attacks — common mistakes

Using XHTML for ordinary websites today
Ignoring EPUB’s XHTML requirement
Feeding lenient HTML into a strict XML pipeline

Boss battleName a real format that still requires XHTML and why.

Example code

<!doctype html><html><head><meta charset="utf-8"></head>
<body style="background:#06040d;color:#e6e0ff;font-family:monospace;padding:20px"><pre>still XHTML today:
  · EPUB e-books (content.xhtml)
  · XML archival / data pipelines
  · MathML/SVG-heavy documents</pre></body></html>

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