LibWeb: Support the :first-of-type CSS selector :^)

3 files changed, 9 insertions, 0 deletions

diff --git a/Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.cpp b/Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.cpp
index 365ed0eee2..a64bcfbae8 100644
--- a/Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.cpp
+++ b/Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.cpp
@@ -554,6 +554,8 @@ public:
                 simple_selector.pseudo_class = CSS::Selector::SimpleSelector::PseudoClass::Empty;
             } else if (pseudo_name.equals_ignoring_case("root")) {
                 simple_selector.pseudo_class = CSS::Selector::SimpleSelector::PseudoClass::Root;
+            } else if (pseudo_name.equals_ignoring_case("first-of-type")) {
+                simple_selector.pseudo_class = CSS::Selector::SimpleSelector::PseudoClass::FirstOfType;
             } else if (pseudo_name.equals_ignoring_case("before")) {
                 simple_selector.pseudo_element = CSS::Selector::SimpleSelector::PseudoElement::Before;
             } else if (pseudo_name.equals_ignoring_case("after")) {
diff --git a/Userland/Libraries/LibWeb/CSS/Selector.h b/Userland/Libraries/LibWeb/CSS/Selector.h
index d5dae94f98..e9d0085206 100644
--- a/Userland/Libraries/LibWeb/CSS/Selector.h
+++ b/Userland/Libraries/LibWeb/CSS/Selector.h
@@ -54,6 +54,7 @@ public:
             OnlyChild,
             Empty,
             Root,
+            FirstOfType,
         };
         PseudoClass pseudo_class { PseudoClass::None };
 
diff --git a/Userland/Libraries/LibWeb/CSS/SelectorEngine.cpp b/Userland/Libraries/LibWeb/CSS/SelectorEngine.cpp
index a1db87f78f..96c0743f89 100644
--- a/Userland/Libraries/LibWeb/CSS/SelectorEngine.cpp
+++ b/Userland/Libraries/LibWeb/CSS/SelectorEngine.cpp
@@ -90,6 +90,12 @@ static bool matches(const CSS::Selector::SimpleSelector& component, const DOM::E
         if (!is<HTML::HTMLElement>(element))
             return false;
         break;
+    case CSS::Selector::SimpleSelector::PseudoClass::FirstOfType:
+        for (auto* sibling = element.previous_element_sibling(); sibling; sibling = sibling->previous_element_sibling()) {
+            if (sibling->tag_name() == element.tag_name())
+                return false;
+        }
+        break;
     }
 
     switch (component.attribute_match_type) {