Elaborate on quirks mode

zcorpan · zcorpan · commit 6670543a2307 · 2015-04-13T11:02:34.000+02:00
diff --git a/Overview.src.html b/Overview.src.html
@@ -240,6 +240,16 @@ <h3 id="doctype">The Doctype</h3>
     that the browser renders the page in standards mode. The doctype has no
     other purpose. <span data-anolis-ref>DOCTYPE</span>
 
+    <p>In HTML4, it was possible to use doctypes that were syntactically correct
+    but still trigger quirks mode (e.g.
+    <code class=bad>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"></code>, without the URL).
+
+    <p>If you were using no doctype or a quirky doctype and switch to a standards mode doctype,
+    you will most likely run into differences between the modes. For example, in quirks mode,
+    classes and IDs in Selectors are case-insensitive and CSS &lt;length>s do not require a unit.
+    For more examples, please refer to
+    <a href="http://www.cs.tut.fi/~jkorpela/quirks-mode.html"><cite>What happens in Quirks Mode?</cite></a>.
+
     <p>The doctype declaration for the HTML syntax is <code>&lt;!DOCTYPE html></code> and is
     case-insensitive. Doctypes from earlier versions of
     HTML were longer because the HTML language was SGML-based and therefore
@@ -2545,6 +2555,7 @@ <h2 class="no-num" id="acknowledgments">Acknowledgments</h2>
     &#x7FBD;&#x7530;&#x91CE;&#x592A;&#x5DF3; (Futomi Hatano),
     Gordon P. Hemsley,
     Henri Sivonen,
+    Jacob Palme,
     James Graham,
     Jens O. Meiert,
     Jeremy Keith,
diff --git a/Overview.whatwg.html b/Overview.whatwg.html
@@ -273,6 +273,16 @@ <h3 id="doctype"><span class="secno">2.2 </span>The Doctype</h3>
     that the browser renders the page in standards mode. The doctype has no
     other purpose. <a href="#refsDOCTYPE">[DOCTYPE]</a>
 
+    <p>In HTML4, it was possible to use doctypes that were syntactically correct
+    but still trigger quirks mode (e.g.
+    <code class="bad">&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"&gt;</code>, without the URL).
+
+    <p>If you were using no doctype or a quirky doctype and switch to a standards mode doctype,
+    you will most likely run into differences between the modes. For example, in quirks mode,
+    classes and IDs in Selectors are case-insensitive and CSS &lt;length&gt;s do not require a unit.
+    For more examples, please refer to
+    <a href="http://www.cs.tut.fi/~jkorpela/quirks-mode.html"><cite>What happens in Quirks Mode?</cite></a>.
+
     <p>The doctype declaration for the HTML syntax is <code>&lt;!DOCTYPE html&gt;</code> and is
     case-insensitive. Doctypes from earlier versions of
     HTML were longer because the HTML language was SGML-based and therefore
@@ -2360,6 +2370,7 @@ <h2 class="no-num" id="acknowledgments">Acknowledgments</h2>
     羽田野太巳 (Futomi Hatano),
     Gordon P. Hemsley,
     Henri Sivonen,
+    Jacob Palme,
     James Graham,
     Jens O. Meiert,
     Jeremy Keith,
