diff --git a/index b/index
index bbf0cbdbf7d..d8bb9a47516 100644
--- a/index
+++ b/index
@@ -33815,10 +33815,10 @@ JSURL: http://ietfreport.isoc.org/all-ids/draft-hoehrmann-javascript-scheme-00.t
     title=dom-navigator-platform><code>platform</code></dfn>
 
    <dd>
-    <p>Must return a string representing the platform on which the browser is
-     executing, e.g. "<code title="">MacIntel</code>", "<code
-     title="">Win32</code>", "<code title="">FreeBSD i386</code>", "<code
-     title="">WebTV OS</code>".
+    <p>Must return either the empty string or a string representing the
+     platform on which the browser is executing, e.g. "<code
+     title="">MacIntel</code>", "<code title="">Win32</code>", "<code
+     title="">FreeBSD i386</code>", "<code title="">WebTV OS</code>".
    </dd>
    <!-- product: Mozilla and Safari only; always returns "Gecko" -->
    <!-- productSub: Mozilla and Safari only; returns same as buildID in Mozilla, and returns the fixed string "20030107" in Safari -->
@@ -33830,7 +33830,8 @@ JSURL: http://ietfreport.isoc.org/all-ids/draft-hoehrmann-javascript-scheme-00.t
 
    <dd>
     <p>Must return the string used for the value of the "<code
-     title="">User-Agent</code>" header in HTTP requests.
+     title="">User-Agent</code>" header in HTTP requests, or the empty string
+     if no such header is ever sent.
    </dd>
    <!-- vendor: Mozilla and Safari only; always returns "" in Mozilla, and returns the fixed string "Apple Computer, Inc." in Safari -->
    <!-- vendorSub: Mozilla and Safari only; always returns "" -->
diff --git a/source b/source
index 7fef5a661a7..59118ac435e 100644
--- a/source
+++ b/source
@@ -31138,7 +31138,7 @@ JSURL: http://ietfreport.isoc.org/all-ids/draft-hoehrmann-javascript-scheme-00.t
    <!-- oscpu: Mozilla only -->
 
    <dt><dfn title="dom-navigator-platform"><code>platform</code></dfn></dt>
-   <dd><p>Must return a string representing the platform on which the browser is executing, e.g. "<code title="">MacIntel</code>", "<code title="">Win32</code>", "<code title="">FreeBSD i386</code>", "<code title="">WebTV OS</code>".</p></dd>
+   <dd><p>Must return either the empty string or a string representing the platform on which the browser is executing, e.g. "<code title="">MacIntel</code>", "<code title="">Win32</code>", "<code title="">FreeBSD i386</code>", "<code title="">WebTV OS</code>".</p></dd>
 
    <!-- product: Mozilla and Safari only; always returns "Gecko" -->
 
@@ -31149,7 +31149,7 @@ JSURL: http://ietfreport.isoc.org/all-ids/draft-hoehrmann-javascript-scheme-00.t
    <!-- taintEnabled(): Opera, IE and Mozilla have this function as one that always returns false -->
 
    <dt><dfn title="dom-navigator-userAgent"><code>userAgent</code></dfn></dt>
-   <dd><p>Must return the string used for the value of the "<code title="">User-Agent</code>" header in HTTP requests.</p></dd>
+   <dd><p>Must return the string used for the value of the "<code title="">User-Agent</code>" header in HTTP requests, or the empty string if no such header is ever sent.</p></dd>
 
    <!-- vendor: Mozilla and Safari only; always returns "" in Mozilla, and returns the fixed string "Apple Computer, Inc." in Safari -->