diff --git a/public/js/script.js b/public/js/script.js
index 50496d3..f6f3a48 100644
--- a/public/js/script.js
+++ b/public/js/script.js
@@ -39,3 +39,11 @@ $(function(){
   });
 
 })
+
+function auto_prefix_url_field(field) {
+  var str = field.value;
+  if(!/^https?:\/\//.test(str)) {
+    str = "http://" + str;
+  }
+  field.value = str;
+}
diff --git a/views/index.php b/views/index.php
index 3ed34c2..b06f097 100644
--- a/views/index.php
+++ b/views/index.php
@@ -8,7 +8,7 @@
     <p>To use Quill, sign in with your domain. Your website will need to support <a href="http://indiewebcamp.com/micropub">Micropub</a> for creating new posts.</p>
 
     <form action="/auth/start" method="get" class="form-inline">
-      <input type="url" name="me" placeholder="http://example.com" value="" class="form-control">
+      <input type="url" name="me" placeholder="https://example.com" value="" class="form-control" onchange="auto_prefix_url_field(this)">
       <input type="submit" value="Sign In" class="btn btn-primary">
       <input type="hidden" name="client_id" value="https://quill.p3k.io">
       <input type="hidden" name="redirect_uri" value="https://quill.p3k.io/auth/callback">