diff --git a/src/components/script/dom/element.rs b/src/components/script/dom/element.rs
index aa092bce325..c384fdca8ce 100644
--- a/src/components/script/dom/element.rs
+++ b/src/components/script/dom/element.rs
@@ -29,7 +29,7 @@ use layout_interface::{MatchSelectorsDocumentDamage};
 use style;
 use servo_util::namespace;
 use servo_util::namespace::{Namespace, Null};
-use servo_util::str::{DOMString, null_str_as_empty_ref};
+use servo_util::str::{DOMString, null_str_as_empty_ref, split_html_space_chars};
 
 use std::ascii::StrAsciiExt;
 use std::cast;
@@ -376,9 +376,8 @@ impl AttributeHandlers for JS<Element> {
     }
 
     fn has_class(&self, name: &str) -> bool {
-        // FIXME: https://github.com/mozilla/servo/issues/1840
         let class_names = self.get_string_attribute("class");
-        let mut classes = class_names.split(' ');
+        let mut classes = split_html_space_chars(class_names);
         classes.any(|class| name == class)
     }
 
diff --git a/src/components/script/dom/htmlcollection.rs b/src/components/script/dom/htmlcollection.rs
index eb56ebac542..e88aedd02db 100644
--- a/src/components/script/dom/htmlcollection.rs
+++ b/src/components/script/dom/htmlcollection.rs
@@ -10,7 +10,7 @@ use dom::element::{Element, AttributeHandlers};
 use dom::node::{Node, NodeHelpers};
 use dom::window::Window;
 use servo_util::namespace::Namespace;
-use servo_util::str::DOMString;
+use servo_util::str::{DOMString, split_html_space_chars};
 
 use serialize::{Encoder, Encodable};
 
@@ -100,7 +100,7 @@ impl HTMLCollection {
             }
         }
         let filter = ClassNameFilter {
-            classes: classes.split(' ').map(|class| class.into_owned()).to_owned_vec()
+            classes: split_html_space_chars(classes).map(|class| class.into_owned()).to_owned_vec()
         };
         HTMLCollection::create(window, root, ~filter)
     }