document array limitations and regexp quantifier over captures

website/guide/limitations.html

@@ -27,6 +27,11 @@ guaranteed to work is about 0.7G characters.</p>
 <p>An object can have at most <code>DUK_HOBJECT_MAX_PROPERTIES</code> (an
 internal define).  Currently this limit is 0x7ffffffff.</p>
 
+<h2>Array limits</h2>
+
+<p>When array item indices go over the 2**31-1 limit (0x7fffffff), Duktape
+has some known bugs with array semantics.</p>
+
 <h2>Regexp quantifier over empty match</h2>
 
 <p>The regexp engine gets stuck when a quantifier is used over an
@@ -43,6 +48,14 @@ RangeError: regexp executor recursion limit
         global input:1 preventsyield
 </pre>
 
+<h2>Regexp quantifier over captures</h2>
+
+<p>When a quantified atom contains captures, the E5.1 specification requires
+that the captures inside the quantified are reset to <code>undefined</code>
+whenever the quantified is re-matched by the quantifier.  Duktape doesn't
+currently do this, which may cause a capture to show through a previous round
+if the capture in question is skipped in quantifier matching.</p>
+
 <h2>Regexp dollar escape</h2>
 
 <p>The Duktape RegExp syntax allows dollar escaping (e.g. <code>/\$/</code>)