1 files changed, 1 insertions, 0 deletions
diff --git a/lib/render.js b/lib/render.js
index e246923..c470ff2 100644
--- a/lib/render.js
+++ b/lib/render.js
@@ -275,6 +275,7 @@ Render.prototype.toUrl = function (href) {
   var m = /^blobstore:(.*)/.exec(href)
   if (m) return this.opts.blob_base + m[1]
   if (/^javascript:/.test(href)) return false
+  if (!/^[a-z0-9]*:/.test(href)) return 'http://' + href
   return href
 }