diff --git a/Parsedown.php b/Parsedown.php
index 0bd81e2..702b041 100644
--- a/Parsedown.php
+++ b/Parsedown.php
@@ -87,7 +87,6 @@ class Parsedown
     protected $safeLinksWhitelist = array(
         'http://',
         'https://',
-        '/',
         'ftp://',
         'ftps://',
         'mailto:',
@@ -1554,7 +1553,14 @@ class Parsedown
 
             if ( ! $safe)
             {
-                unset($Element['attributes'][$attribute]);
+                $Element['attributes'][$attribute] = preg_replace_callback(
+                    '/[^\/#?&=%]++/',
+                    function (array $match)
+                    {
+                        return urlencode($match[0]);
+                    },
+                    $Element['attributes'][$attribute]
+                );
             }
         }
 
diff --git a/test/data/inline_link.html b/test/data/inline_link.html
index cef29cf..7a3131b 100644
--- a/test/data/inline_link.html
+++ b/test/data/inline_link.html
@@ -1,5 +1,5 @@
 <p><a href="http://example.com">link</a></p>
-<p><a href="/url-(parentheses)">link</a> with parentheses in URL </p>
+<p><a href="/url-%28parentheses%29">link</a> with parentheses in URL </p>
 <p>(<a href="/index.php">link</a>) in parentheses</p>
 <p><a href="http://example.com"><code>link</code></a></p>
 <p><a href="http://example.com"><img src="http://parsedown.org/md.png" alt="MD Logo" /></a></p>
diff --git a/test/data/xss_bad_url.html b/test/data/xss_bad_url.html
index 93dd0d8..8e43877 100644
--- a/test/data/xss_bad_url.html
+++ b/test/data/xss_bad_url.html
@@ -1,16 +1,16 @@
-<p><a>xss</a></p>
-<p><a>xss</a></p>
-<p><a>xss</a></p>
-<p><a>xss</a></p>
-<p><img alt="xss" /></p>
-<p><img alt="xss" /></p>
-<p><img alt="xss" /></p>
-<p><img alt="xss" /></p>
-<p><a>xss</a></p>
-<p><a>xss</a></p>
-<p><a>xss</a></p>
-<p><a>xss</a></p>
-<p><img alt="xss" /></p>
-<p><img alt="xss" /></p>
-<p><img alt="xss" /></p>
-<p><img alt="xss" /></p>
\ No newline at end of file
+<p><a href="javascript%3Aalert%281%29">xss</a></p>
+<p><a href="javascript%3Aalert%281%29">xss</a></p>
+<p><a href="javascript%3A//alert%281%29">xss</a></p>
+<p><a href="javascript&amp;colon%3Balert%281%29">xss</a></p>
+<p><img src="javascript%3Aalert%281%29" alt="xss" /></p>
+<p><img src="javascript%3Aalert%281%29" alt="xss" /></p>
+<p><img src="javascript%3A//alert%281%29" alt="xss" /></p>
+<p><img src="javascript&amp;colon%3Balert%281%29" alt="xss" /></p>
+<p><a href="data%3Atext/html%3Bbase64%2CPHNjcmlwdD5hbGVydCgxKTwvc2NyaXB0Pg==">xss</a></p>
+<p><a href="data%3Atext/html%3Bbase64%2CPHNjcmlwdD5hbGVydCgxKTwvc2NyaXB0Pg==">xss</a></p>
+<p><a href="data%3A//text/html%3Bbase64%2CPHNjcmlwdD5hbGVydCgxKTwvc2NyaXB0Pg==">xss</a></p>
+<p><a href="data&amp;colon%3Btext/html%3Bbase64%2CPHNjcmlwdD5hbGVydCgxKTwvc2NyaXB0Pg==">xss</a></p>
+<p><img src="data%3Atext/html%3Bbase64%2CPHNjcmlwdD5hbGVydCgxKTwvc2NyaXB0Pg==" alt="xss" /></p>
+<p><img src="data%3Atext/html%3Bbase64%2CPHNjcmlwdD5hbGVydCgxKTwvc2NyaXB0Pg==" alt="xss" /></p>
+<p><img src="data%3A//text/html%3Bbase64%2CPHNjcmlwdD5hbGVydCgxKTwvc2NyaXB0Pg==" alt="xss" /></p>
+<p><img src="data&amp;colon%3Btext/html%3Bbase64%2CPHNjcmlwdD5hbGVydCgxKTwvc2NyaXB0Pg==" alt="xss" /></p>
\ No newline at end of file