diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -60,9 +60,9 @@
 
 Using cabal:
 
-    cabal install -fbootstrap --disable-optimizations
+    cabal install -fbootstrap --disable-optimization
     cabal run skylighting-extract -- xml/*.xml
-    cabal install -f-bootstrap --disable-optimizations
+    cabal install -f-bootstrap --disable-optimization
 
 Command-line tool
 -----------------
diff --git a/bin/main.hs b/bin/main.hs
--- a/bin/main.hs
+++ b/bin/main.hs
@@ -216,8 +216,14 @@
 hlHtml frag fname opts sty sourceLines =
  if frag
     then putStrLn $ renderHtml fragment
-    else putStrLn $ renderHtml $ H.html $
-           H.head (pageTitle >> metadata >> css) >> H.body (H.toHtml fragment)
+    else putStrLn $ renderHtml $ do
+           H.docType
+           H.html $ do
+             H.head $ do
+               pageTitle
+               metadata
+               css
+             H.body $ H.toHtml fragment
   where fragment = formatHtmlBlock opts sourceLines
         css = H.style H.! A.type_ "text/css" $ H.toHtml $ styleToCss sty
         pageTitle = H.title $ H.toHtml fname
diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,14 @@
 # Revision history for skylighting
 
+## 0.4.4 -- 2017-11-21
+
+  * HTML formatter: always use an a element (rather than a div)
+    for source lines.  The divs were invalid, because code
+    elements must contain phrasing content.  Previously we used
+    a elements when line anchors were called for, but there is
+    no clear reason not to use them always.
+  * skylighting binary: add doctype to generated HTML.
+
 ## 0.4.3.2 -- 2017-11-04
 
   * Fixed regression in `data-line-number` attributes in HTML
diff --git a/skylighting.cabal b/skylighting.cabal
--- a/skylighting.cabal
+++ b/skylighting.cabal
@@ -1,5 +1,5 @@
 name:                skylighting
-version:             0.4.3.2
+version:             0.4.4
 synopsis:            syntax highlighting library
 description:         Skylighting is a syntax highlighting library with
                      support for over one hundred languages.  It derives
diff --git a/src/Skylighting/Format/HTML.hs b/src/Skylighting/Format/HTML.hs
--- a/src/Skylighting/Format/HTML.hs
+++ b/src/Skylighting/Format/HTML.hs
@@ -52,13 +52,11 @@
                       . mconcat . intersperse (toHtml "\n")
                       . map (mapM_ (tokenToHtml opts))
 
--- | Format tokens as an HTML @pre@ block. Each line is wrapped in a div
--- with the class ‘source-line’. If line numbering
--- is selected, this surrounding div is given the class ‘number-source’,
+-- | Format tokens as an HTML @pre@ block. Each line is wrapped in an a
+-- element with the class ‘source-line’. If line numbering
+-- is selected, the surrounding pre is given the class ‘numberSource’,
 -- and the resulting html will display line numbers thanks to the included
--- css. Note that the html produced will always include the line numbers as
--- the 'data-line-number' attribute.
--- See the documentation for 'formatHtmlInline' for information about how
+-- CSS.  See the documentation for 'formatHtmlInline' for information about how
 -- tokens are encoded.
 formatHtmlBlock :: FormatOptions -> [SourceLine] -> Html
 formatHtmlBlock opts ls =
@@ -77,7 +75,7 @@
                                              $ Text.pack "sourceCode"
                                                : codeClasses opts) $ h
 
--- | Each line of source is wrapped in an (inline-block) div that makes
+-- | Each line of source is wrapped in an (inline-block) anchor that makes
 -- subsequent per-line processing (e.g. adding line numnbers) possible.
 sourceLineToHtml :: FormatOptions -> LineNo -> SourceLine -> Html
 sourceLineToHtml opts lno cont =
@@ -86,7 +84,7 @@
                  ! A.id lineNum
                  ! A.href lineRef
                  ! dataAttrib
-      else H.div ! A.class_ sourceLine
+      else H.a   ! A.class_ sourceLine
                  ! A.id lineNum
                  ! dataAttrib) $ mapM_ (tokenToHtml opts) cont
   where  sourceLine = toValue "sourceLine"
@@ -147,9 +145,9 @@
                           (Just c1, Just c2) -> ["pre, code { color: " ++ fromColor c1 ++ "; background-color: " ++
                                                   fromColor c2 ++ "; }"]
          numberspec = [
-            "pre.numberSource div.sourceLine, .numberSource a.sourceLine"
+            "pre.numberSource a.sourceLine"
           , "  { position: relative; }"
-          , "pre.numberSource div.sourceLine::before, .numberSource a.sourceLine::before"
+          , "pre.numberSource a.sourceLine::before"
           , "  { content: attr(data-line-number);"
           , "    position: absolute; left: -5em; text-align: right; vertical-align: baseline;"
           , "    border: none; pointer-events: all;"
@@ -164,13 +162,13 @@
               " padding-left: 4px; }"
           ]
          divspec = [
-            "div.sourceLine, a.sourceLine { display: inline-block; min-height: 1.25em; }"
+            "a.sourceLine { display: inline-block; min-height: 1.25em; }"
           , "a.sourceLine { pointer-events: none; color: inherit; text-decoration: inherit; }"
           , ".sourceCode { overflow: visible; }"
           , "code.sourceCode { white-space: pre; }"
           , "@media print {"
           , "code.sourceCode { white-space: pre-wrap; }"
-          , "div.sourceLine, a.sourceLine { text-indent: -1em; padding-left: 1em; }"
+          , "a.sourceLine { text-indent: -1em; padding-left: 1em; }"
           , "}"
           ]
          linkspec = [ "@media screen {"