diff --git a/graph b/graph
index 3fd98dc..786096c 100755
--- a/graph
+++ b/graph
@@ -70,21 +70,21 @@ then
 			<table style="width:$(( graph_width + 97 ))px">
 				<tr>
 					<td>
-						<a href="?start=$(( start - 604800 ))&end=$end">&lt;&lt;</a>
-						<a href="?start=$(( start - 86400 ))&end=$end">&lt;</a>
-						<a href="?start=$default_start&end=$end">R</a>
-						<a href="?start=$(( start + 86400 ))&end=$end">&gt;</a>
-						<a href="?start=$(( start + 604800 ))&end=$end">&gt;&gt;</a>
+						<a href="?start=$(( start - 604800 ))&amp;end=$end">&lt;&lt;</a>
+						<a href="?start=$(( start - 86400 ))&amp;end=$end">&lt;</a>
+						<a href="?start=$default_start&amp;end=$end">R</a>
+						<a href="?start=$(( start + 86400 ))&amp;end=$end">&gt;</a>
+						<a href="?start=$(( start + 604800 ))&amp;end=$end">&gt;&gt;</a>
 					</td>
 					<td align="center">
-						<div align="center"><a href="add.html">Add data</a></div>
+						<a href="add.html">Add data</a>
 					</td>
 					<td align="right">
-						<a href="?start=$start&end=$(( end - 604800 ))">&lt;&lt;</a>
-						<a href="?start=$start&end=$(( end - 86400 ))">&lt;</a>
-						<a href="?start=$start&end=$default_end">R</a>
-						<a href="?start=$start&end=$(( end + 86400 ))">&gt;</a>
-						<a href="?start=$start&end=$(( end + 604800 ))">&gt;&gt;</a>
+						<a href="?start=$start&amp;end=$(( end - 604800 ))">&lt;&lt;</a>
+						<a href="?start=$start&amp;end=$(( end - 86400 ))">&lt;</a>
+						<a href="?start=$start&amp;end=$default_end">R</a>
+						<a href="?start=$start&amp;end=$(( end + 86400 ))">&gt;</a>
+						<a href="?start=$start&amp;end=$(( end + 604800 ))">&gt;&gt;</a>
 					</td>
 				</tr>
 			</table>
@@ -97,11 +97,27 @@ then
 	do
 		cat <<-EOHTML
 			<div>
-				<img src="graph?graph=$stat&start=$start&end=$end" />
+				<img
+					src="graph?graph=$stat&amp;start=$start&amp;end=$end"
+					alt="Ingress $graph evolution" />
 			</div>
 		EOHTML
 	done
+	encodeduri="${REQUEST_URI//\//%2F}"
+	encodeduri="${encodeduri/\?/%3F}"
+	encodeduri="${encodeduri//\=/%3D}"
+	encodeduri="${encodeduri//\&/%26}"
 	cat <<-EOHTML
+			<p>
+				<a
+					href="http://validator.w3.org/check?uri=https%3A%2F%2F$SERVER_NAME$encodeduri">
+					<img
+						src="/valid-xhtml11"
+						alt="Valid XHTML 1.1"
+						height="31"
+						width="88" />
+				</a>
+			</p>
 		</body></html>
 	EOHTML
 else