listen to hashchange event

index.html

@@ -21,12 +21,17 @@
 
 	<script type="text/javascript">
 	function generateQR() {
-		new QRCode(document.getElementById("qrcode"), location.hash.substring(1));
+		var qrcode = new QRCode(document.getElementById("qrcode"), location.hash.substring(1));
 	}
 	$( document ).ready(function() {
 		generateQR();
 	});
 
+	window.addEventListener('hashchange', function() {
+		qrcode.clear(); 
+		qrcode.makeCode(location.hash.substring(1));
+	});
+			
 	</script>
 
 	<footer>