fix js.

Author: csyonghe

docs/_layouts/stdlib-reference.html

@@ -297,7 +297,8 @@
       event.stopPropagation();
     }
     var path = window.location.pathname;
-    var pageName = path.split("/").pop();
+    var firstSlash = path.indexOf("/");
+    var pageName = path.substr(firstSlash);
     var currentPageID = pageName.substr(0, pageName.lastIndexOf("."));
     if (currentPageID.length == 0)
       currentPageID = "index";