diff --git a/complete.html b/complete.html
index cc2b32b6257..e7d9b213d5e 100644
--- a/complete.html
+++ b/complete.html
@@ -42291,7 +42291,7 @@ <h4 id=the-input-element><span class=secno>4.10.7 </span>The <dfn><code>input</c
            attribute DOMString <a href=#dom-input-type title=dom-input-type>type</a>;
            attribute DOMString <a href=#dom-input-defaultvalue title=dom-input-defaultValue>defaultValue</a>;
            attribute DOMString <a href=#dom-input-value title=dom-input-value>value</a>;
-           attribute <span>Date</span> <a href=#dom-input-valueasdate title=dom-input-valueAsDate>valueAsDate</a>;
+           attribute <span>Date</span>? <a href=#dom-input-valueasdate title=dom-input-valueAsDate>valueAsDate</a>;
            attribute double <a href=#dom-input-valueasnumber title=dom-input-valueAsNumber>valueAsNumber</a>;
            attribute unsigned long <a href=#dom-input-width title=dom-input-width>width</a>;
 
diff --git a/index b/index
index cc2b32b6257..e7d9b213d5e 100644
--- a/index
+++ b/index
@@ -42291,7 +42291,7 @@ interface <dfn id=htmlformelement>HTMLFormElement</dfn> : <a href=#htmlelement>H
            attribute DOMString <a href=#dom-input-type title=dom-input-type>type</a>;
            attribute DOMString <a href=#dom-input-defaultvalue title=dom-input-defaultValue>defaultValue</a>;
            attribute DOMString <a href=#dom-input-value title=dom-input-value>value</a>;
-           attribute <span>Date</span> <a href=#dom-input-valueasdate title=dom-input-valueAsDate>valueAsDate</a>;
+           attribute <span>Date</span>? <a href=#dom-input-valueasdate title=dom-input-valueAsDate>valueAsDate</a>;
            attribute double <a href=#dom-input-valueasnumber title=dom-input-valueAsNumber>valueAsNumber</a>;
            attribute unsigned long <a href=#dom-input-width title=dom-input-width>width</a>;
 
diff --git a/source b/source
index 17ed2dc7175..4f85c628a73 100644
--- a/source
+++ b/source
@@ -49370,7 +49370,7 @@ interface <dfn>HTMLFormElement</dfn> : <span>HTMLElement</span> {
            attribute DOMString <span title="dom-input-type">type</span>;
            attribute DOMString <span title="dom-input-defaultValue">defaultValue</span>;
            attribute DOMString <span title="dom-input-value">value</span>;
-           attribute <span>Date</span> <span title="dom-input-valueAsDate">valueAsDate</span>;
+           attribute <span>Date</span>? <span title="dom-input-valueAsDate">valueAsDate</span>;
            attribute double <span title="dom-input-valueAsNumber">valueAsNumber</span>;
            attribute unsigned long <span title="dom-input-width">width</span>;