diff --git a/src/pyj/dom.pyj b/src/pyj/dom.pyj
index ed6e0c30d8..a4d80bff63 100644
--- a/src/pyj/dom.pyj
+++ b/src/pyj/dom.pyj
@@ -25,6 +25,8 @@ simple_vendor_prefixes = {
 }
 
 def set_css(elem, **kw):
+    if type(elem) is 'string':
+        elem = document.querySelector(elem)
     s = elem.style
     if s:
         for prop in kw: