diff --git a/lisp/org-html.el b/lisp/org-html.el
index d5f477558..221cbf6fb 100644
--- a/lisp/org-html.el
+++ b/lisp/org-html.el
@@ -640,7 +640,7 @@ MAY-INLINE-P allows inlining it as an image."
(setq thefile
(let
((str (org-export-html-format-href thefile)))
- (if type
+ (if (and type (string-match-p "^//" str))
(concat type ":" str)
str)))