2 files changed, 26 insertions, 2 deletions
diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index 155098247b6..234a10f9448 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -3235,6 +3235,18 @@ impl Element {
         let root = node.GetRootNode();
         root.is::<Document>()
     }
+
+    // https://html.spec.whatwg.org/multipage/#cannot-navigate
+    pub fn cannot_navigate(&self) -> bool {
+        let document = document_from_node(self);
+
+        // Step 1.
+        !document.is_fully_active() ||
+            (
+                // Step 2.
+                !self.is::<HTMLAnchorElement>() && !self.is_connected()
+            )
+    }
 }
 
 impl Element {
diff --git a/components/script/dom/htmlformelement.rs b/components/script/dom/htmlformelement.rs
index 6a4a4b97fe5..e81613d750d 100755
--- a/components/script/dom/htmlformelement.rs
+++ b/components/script/dom/htmlformelement.rs
@@ -317,7 +317,11 @@ impl HTMLFormElement {
 
     /// [Form submission](https://html.spec.whatwg.org/multipage/#concept-form-submit)
     pub fn submit(&self, submit_method_flag: SubmittedFrom, submitter: FormSubmitter) {
-        // TODO: Step 1. If form cannot navigate , then return.
+        // Step 1
+        if self.upcast::<Element>().cannot_navigate() {
+            return;
+        }
+
         // Step 2
         if self.constructing_entry_list.get() {
             return;
@@ -342,6 +346,11 @@ impl HTMLFormElement {
             if event.DefaultPrevented() {
                 return;
             }
+
+            // Step 7-3
+            if self.upcast::<Element>().cannot_navigate() {
+                return;
+            }
         }
 
         // Step 8
@@ -353,7 +362,10 @@ impl HTMLFormElement {
             None => return,
         };
 
-        // TODO: Step 10. If form cannot navigate, then return.
+        // Step 10
+        if self.upcast::<Element>().cannot_navigate() {
+            return;
+        }
 
         // Step 11
         let mut action = submitter.action();