diff --git a/www/index.php b/www/index.php
index 2957746ba1b89f0ad55e6ad4ecec6afdc1d69763..7d928878685b9ce8fc1e3c6c83d531404878ae9f 100644
--- a/www/index.php
+++ b/www/index.php
@@ -82,7 +82,15 @@ if (isset($_GET['uri'])
             </form>
             <div class="clear">
                 <pre>
-                <?php 
+                <?php
+                if (!empty($uri)) {
+                    $parts = parse_url($uri);
+                    if (!isset($parts['path'])) {
+                        echo '<h2>tsk tsk. A trailing slash is always required. Didn\'t your mother ever teach you what a web address is?</h2>';
+                        unset($uri);
+                    }
+                }
+                
                 if (!empty($uri)) {
                     $assessment = new UNL_WDN_Assessment($uri, $db);
                     $action = 'rescan';