diff --git a/Libraries/LibWeb/DOM/AttributeNames.h b/Libraries/LibWeb/DOM/AttributeNames.h
index 90e8f22be8..86deac13d4 100644
--- a/Libraries/LibWeb/DOM/AttributeNames.h
+++ b/Libraries/LibWeb/DOM/AttributeNames.h
@@ -54,7 +54,8 @@ void initialize();
     __ENUMERATE_HTML_ATTRIBUTE(async)   \
     __ENUMERATE_HTML_ATTRIBUTE(defer)   \
     __ENUMERATE_HTML_ATTRIBUTE(bgcolor) \
-    __ENUMERATE_HTML_ATTRIBUTE(size)
+    __ENUMERATE_HTML_ATTRIBUTE(size)    \
+    __ENUMERATE_HTML_ATTRIBUTE(colspan)
 
 #define __ENUMERATE_HTML_ATTRIBUTE(name) extern FlyString name;
 ENUMERATE_HTML_ATTRIBUTES