diff --git a/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.h b/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.h
index 79a81877889a6..62be62dada8d2 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.h
+++ b/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.h
@@ -30,8 +30,8 @@ class CSSStyleDeclaration : public Bindings::PlatformObject {
     virtual WebIDL::ExceptionOr<void> set_property(PropertyID, StringView css_text, StringView priority = ""sv) = 0;
     virtual WebIDL::ExceptionOr<String> remove_property(PropertyID) = 0;
 
-    WebIDL::ExceptionOr<void> set_property(StringView property_name, StringView css_text, StringView priority);
-    WebIDL::ExceptionOr<String> remove_property(StringView property_name);
+    virtual WebIDL::ExceptionOr<void> set_property(StringView property_name, StringView css_text, StringView priority);
+    virtual WebIDL::ExceptionOr<String> remove_property(StringView property_name);
 
     String get_property_value(StringView property) const;
     StringView get_property_priority(StringView property) const;
diff --git a/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp b/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp
index 80e6c04a3f97b..da2b5991fbfc4 100644
--- a/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp
+++ b/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp
@@ -569,18 +569,42 @@ Optional<StyleProperty> ResolvedCSSStyleDeclaration::property(PropertyID propert
     };
 }
 
+static WebIDL::ExceptionOr<void> cannot_modify_computed_properties_error(JS::Realm& realm)
+{
+    return WebIDL::NoModificationAllowedError::create(realm, "Cannot modify properties in result of getComputedStyle()"_fly_string);
+}
+
 // https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-setproperty
 WebIDL::ExceptionOr<void> ResolvedCSSStyleDeclaration::set_property(PropertyID, StringView, StringView)
 {
     // 1. If the computed flag is set, then throw a NoModificationAllowedError exception.
-    return WebIDL::NoModificationAllowedError::create(realm(), "Cannot modify properties in result of getComputedStyle()"_fly_string);
+    return cannot_modify_computed_properties_error(realm());
+}
+
+// https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-setproperty
+WebIDL::ExceptionOr<void> ResolvedCSSStyleDeclaration::set_property(StringView, StringView, StringView)
+{
+    // 1. If the computed flag is set, then throw a NoModificationAllowedError exception.
+    return cannot_modify_computed_properties_error(realm());
+}
+
+static WebIDL::ExceptionOr<String> cannot_remove_computed_properties_error(JS::Realm& realm)
+{
+    return WebIDL::NoModificationAllowedError::create(realm, "Cannot remove properties from result of getComputedStyle()"_fly_string);
 }
 
 // https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-removeproperty
 WebIDL::ExceptionOr<String> ResolvedCSSStyleDeclaration::remove_property(PropertyID)
 {
     // 1. If the computed flag is set, then throw a NoModificationAllowedError exception.
-    return WebIDL::NoModificationAllowedError::create(realm(), "Cannot remove properties from result of getComputedStyle()"_fly_string);
+    return cannot_remove_computed_properties_error(realm());
+}
+
+// https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-removeproperty
+WebIDL::ExceptionOr<String> ResolvedCSSStyleDeclaration::remove_property(StringView)
+{
+    // 1. If the computed flag is set, then throw a NoModificationAllowedError exception.
+    return cannot_remove_computed_properties_error(realm());
 }
 
 String ResolvedCSSStyleDeclaration::serialized() const
diff --git a/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.h b/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.h
index 422f82d1a3e8a..7dfd76bd98969 100644
--- a/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.h
+++ b/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.h
@@ -24,7 +24,9 @@ class ResolvedCSSStyleDeclaration final : public CSSStyleDeclaration {
 
     virtual Optional<StyleProperty> property(PropertyID) const override;
     virtual WebIDL::ExceptionOr<void> set_property(PropertyID, StringView css_text, StringView priority) override;
+    virtual WebIDL::ExceptionOr<void> set_property(StringView property_name, StringView css_text, StringView priority) override;
     virtual WebIDL::ExceptionOr<String> remove_property(PropertyID) override;
+    virtual WebIDL::ExceptionOr<String> remove_property(StringView property_name) override;
 
     virtual String serialized() const override;
     virtual WebIDL::ExceptionOr<void> set_css_text(StringView) override;