Join tokens when stringifying DOMTokenList

Previous, it would return the original String straight from the
AttrValue, which might contain extraaneous whitespace. The spec
specifies to just join the tokens together with \x20

https://dom.spec.whatwg.org/#stringification-behavior

1 files changed, 6 insertions, 1 deletions

diff --git a/components/script/dom/domtokenlist.rs b/components/script/dom/domtokenlist.rs
index b3656ae4b7c..f863996e9ca 100644
--- a/components/script/dom/domtokenlist.rs
+++ b/components/script/dom/domtokenlist.rs
@@ -157,6 +157,11 @@ impl<'a> DOMTokenListMethods for &'a DOMTokenList {
 
     // https://dom.spec.whatwg.org/#stringification-behavior
     fn Stringifier(self) -> DOMString {
-        self.element.root().r().get_string_attribute(&self.local_name)
+        let tokenlist = self.element.root().r().get_tokenlist_attribute(&self.local_name);
+        tokenlist.iter().fold(String::new(), |mut s, atom| {
+            if !s.is_empty() { s.push('\x20'); }
+            s.push_str(atom);
+            s
+        })
     }
 }