diff --git a/gridstack.js b/gridstack.js
index c18535c..1b28bad 100644
--- a/gridstack.js
+++ b/gridstack.js
@@ -34,7 +34,7 @@
             else {
                 style.appendChild(document.createTextNode(""));
             }
-            document.head.appendChild(style);
+            document.getElementsByTagName('head')[0].appendChild(style);
             return style.sheet;
         },