1 files changed, 2 insertions, 1 deletions
diff --git a/components/script/dom/cssstyledeclaration.rs b/components/script/dom/cssstyledeclaration.rs
index ae62ebb483e..e36652c446a 100644
--- a/components/script/dom/cssstyledeclaration.rs
+++ b/components/script/dom/cssstyledeclaration.rs
@@ -15,6 +15,7 @@ use dom::node::{Node, NodeDamage, window_from_node};
 use dom::window::Window;
 use std::ascii::AsciiExt;
 use std::slice;
+use std::sync::Arc;
 use string_cache::Atom;
 use style::parser::ParserContextExtraData;
 use style::properties::{PropertyDeclaration, Shorthand, Importance};
@@ -367,7 +368,7 @@ impl CSSStyleDeclarationMethods for CSSStyleDeclaration {
         *element.style_attribute().borrow_mut() = if decl_block.declarations.is_empty() {
             None // Step 2
         } else {
-            Some(decl_block)
+            Some(Arc::new(decl_block))
         };
         element.sync_property_with_attrs_style();
         let node = element.upcast::<Node>();