2 files changed, 3 insertions, 3 deletions
diff --git a/components/script/dom/htmlformelement.rs b/components/script/dom/htmlformelement.rs
index 0922902778a..32838399a93 100644
--- a/components/script/dom/htmlformelement.rs
+++ b/components/script/dom/htmlformelement.rs
@@ -205,8 +205,8 @@ impl HTMLFormElementMethods for HTMLFormElement {
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-form-length
-    fn Length(&self) -> i32 {
-        self.Elements().Length() as i32
+    fn Length(&self) -> u32 {
+        self.Elements().Length() as u32
     }
 }
 
diff --git a/components/script/dom/webidls/HTMLFormElement.webidl b/components/script/dom/webidls/HTMLFormElement.webidl
index d97de7dd22d..eebe0b52c62 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 unsigned long length;
   //getter Element (unsigned long index);
   //getter (RadioNodeList or Element) (DOMString name);