1 files changed, 8 insertions, 0 deletions
diff --git a/components/script/dom/webidls/HTMLFormElement.webidl b/components/script/dom/webidls/HTMLFormElement.webidl
index b4a2504fd60..1514e38b6f5 100644
--- a/components/script/dom/webidls/HTMLFormElement.webidl
+++ b/components/script/dom/webidls/HTMLFormElement.webidl
@@ -35,3 +35,11 @@ interface HTMLFormElement : HTMLElement {
   //boolean checkValidity();
   //boolean reportValidity();
 };
+
+// https://html.spec.whatwg.org/multipage/#selectionmode
+enum SelectionMode {
+  "preserve", // default
+  "select",
+  "start",
+  "end"
+};