1 files changed, 7 insertions, 1 deletions
diff --git a/components/style/selector_matching.rs b/components/style/selector_matching.rs
index 5482745721f..091d6204886 100644
--- a/components/style/selector_matching.rs
+++ b/components/style/selector_matching.rs
@@ -23,7 +23,7 @@ use properties::{PropertyDeclaration, PropertyDeclarationBlock};
 use selectors::{After, AnyLink, AttrDashMatch, AttrEqual};
 use selectors::{AttrExists, AttrIncludes, AttrPrefixMatch};
 use selectors::{AttrSubstringMatch, AttrSuffixMatch, Before, CaseInsensitive, CaseSensitive};
-use selectors::{Checked, Child, ClassSelector};
+use selectors::{Checked, Child, ClassSelector, Indeterminate};
 use selectors::{CompoundSelector, Descendant, Disabled, Enabled, FirstChild, FirstOfType};
 use selectors::{Hover, IDSelector, LastChild, LastOfType};
 use selectors::{LaterSibling, LocalName, LocalNameSelector};
@@ -972,6 +972,12 @@ pub fn matches_simple_selector<'a,E,N>(selector: &SimpleSelector,
             let elem = element.as_element();
             elem.get_checked_state()
         }
+        // https://html.spec.whatwg.org/multipage/scripting.html#selector-indeterminate
+        Indeterminate => {
+            *shareable = false;
+            let elem = element.as_element();
+            elem.get_indeterminate_state()
+        }
         FirstChild => {
             *shareable = false;
             matches_first_child(element)