2 files changed, 6 insertions, 1 deletions
diff --git a/components/script/dom/htmlformelement.rs b/components/script/dom/htmlformelement.rs
index 072231d4054..43cf6bce3ce 100644
--- a/components/script/dom/htmlformelement.rs
+++ b/components/script/dom/htmlformelement.rs
@@ -195,6 +195,11 @@ impl HTMLFormElementMethods for HTMLFormElement {
         let window = window_from_node(self);
         HTMLFormControlsCollection::new(window.r(), self.upcast(), filter)
     }
+
+    // https://html.spec.whatwg.org/multipage/#dom-form-length
+    fn Length(&self) -> i32 {
+        self.Elements().Length() as i32
+    }
 }
 
 #[derive(Copy, Clone, HeapSizeOf, PartialEq)]
diff --git a/components/script/dom/webidls/HTMLFormElement.webidl b/components/script/dom/webidls/HTMLFormElement.webidl
index 4fde856a6a5..d97de7dd22d 100644
--- a/components/script/dom/webidls/HTMLFormElement.webidl
+++ b/components/script/dom/webidls/HTMLFormElement.webidl
@@ -17,7 +17,7 @@ interface HTMLFormElement : HTMLElement {
            attribute DOMString target;
 
   [SameObject] readonly attribute HTMLFormControlsCollection elements;
-  //readonly attribute long length;
+  readonly attribute long length;
   //getter Element (unsigned long index);
   //getter (RadioNodeList or Element) (DOMString name);