Support lang pseudo class

1 files changed, 5 insertions, 0 deletions

diff --git a/components/script/layout_wrapper.rs b/components/script/layout_wrapper.rs
index 000a844bc16..071868a683f 100644
--- a/components/script/layout_wrapper.rs
+++ b/components/script/layout_wrapper.rs
@@ -53,6 +53,7 @@ use selectors::matching::ElementSelectorFlags;
 use selectors::parser::{AttrSelector, NamespaceConstraint};
 use servo_atoms::Atom;
 use servo_url::ServoUrl;
+use std::ascii::AsciiExt;
 use std::fmt;
 use std::fmt::Debug;
 use std::marker::PhantomData;
@@ -618,6 +619,10 @@ impl<'le> ::selectors::Element for ServoLayoutElement<'le> {
             },
             NonTSPseudoClass::Visited => false,
 
+            // FIXME(#15746): This is wrong, we need to instead use extended filtering as per RFC4647
+            //                https://tools.ietf.org/html/rfc4647#section-3.3.2
+            NonTSPseudoClass::Lang(ref lang) => lang.eq_ignore_ascii_case(&self.element.get_lang_for_layout()),
+
             NonTSPseudoClass::ServoNonZeroBorder => unsafe {
                 match (*self.element.unsafe_get()).get_attr_for_layout(&ns!(), &local_name!("border")) {
                     None | Some(&AttrValue::UInt(_, 0)) => false,