diff --git a/lib/url.js b/lib/url.js
index 4b142542..34feba5a 100644
--- a/lib/url.js
+++ b/lib/url.js
@@ -1,4 +1,5 @@
 export function ensureProtocol (value) {
+  value = value.trim()
   if (!/^([a-z0-9]+:\/\/|mailto:)/.test(value)) {
     value = 'http://' + value
   }