diff --git a/frontend/images/ladebild.gif b/frontend/images/ladebild.gif
deleted file mode 100644
index 2014bb8..0000000
Binary files a/frontend/images/ladebild.gif and /dev/null differ
diff --git a/frontend/images/loading.gif b/frontend/images/loading.gif
new file mode 100644
index 0000000..c69e937
Binary files /dev/null and b/frontend/images/loading.gif differ
diff --git a/frontend/javascripts/frontend.js b/frontend/javascripts/frontend.js
index 4fd02b3..4c350bb 100644
--- a/frontend/javascripts/frontend.js
+++ b/frontend/javascripts/frontend.js
@@ -324,7 +324,7 @@ vz.entities.each = function(cb) {
  */
 vz.plot.data.load = function() {
 	vz.plot.data.clear();
-	$('#plot').html('<div id="loading">loading...</div>');	// TODO insert loading animation
+	$('#plot').html('<div id="loading"><img src="images/loading.gif" alt="loading..." /><p>Loading...</p></div>');	// TODO insert loading animation
 	vz.entities.each(function(entity, parent) {
 		if (entity.active && entity.type != 'group') {
 			$.getJSON(vz.options.backendUrl + '/data/' + entity.uuid + '.json', { from: Math.floor(vz.from), to: Math.ceil(vz.to), tuples: vz.options.tuples }, waitAsync(function(json) {
diff --git a/frontend/javascripts/uuid.js b/frontend/javascripts/uuid.js
index 63fe718..c2b11eb 100644
--- a/frontend/javascripts/uuid.js
+++ b/frontend/javascripts/uuid.js
@@ -71,5 +71,5 @@ vz.uuids.remove = function(uuid) {
  * Validate UUID
  */
 vz.uuids.validate = function(uuid) {
-	return new uuid.match(/^[0-9a-zA-Z]{8}-[0-9a-zA-Z]{4}-[0-9a-zA-Z]{4}-[0-9a-zA-Z]{4}-[0-9a-zA-Z]{12}$/) > 0;
+	return uuid.match(/^[0-9a-zA-Z]{8}-[0-9a-zA-Z]{4}-[0-9a-zA-Z]{4}-[0-9a-zA-Z]{4}-[0-9a-zA-Z]{12}$/);
 };
\ No newline at end of file
diff --git a/frontend/stylesheets/style.css b/frontend/stylesheets/style.css
index 0cfab98..8622a00 100644
--- a/frontend/stylesheets/style.css
+++ b/frontend/stylesheets/style.css
@@ -121,6 +121,10 @@ tbody tr td {
 	text-align: right;
 }
 
-.loading {
-	/* TODO center */
-}	
\ No newline at end of file
+#loading {
+	display: block;
+	margin: auto;
+	padding-top: 150px;
+	text-align: center;
+	color: grey;
+}