diff --git a/web/includes/functions.php b/web/includes/functions.php
index a3723c635..85e3b022c 100644
--- a/web/includes/functions.php
+++ b/web/includes/functions.php
@@ -56,6 +56,7 @@ function CSPHeaders($view, $nonce) {
     case 'download':
     case 'error':
     case 'export':
+    case 'frame':
     case 'function':
     case 'log':
     case 'logout':
diff --git a/web/skins/classic/css/base/views/frame.css b/web/skins/classic/css/base/views/frame.css
index c9cb1846c..947fee1bc 100644
--- a/web/skins/classic/css/base/views/frame.css
+++ b/web/skins/classic/css/base/views/frame.css
@@ -9,8 +9,3 @@
     display: flex;
     justify-content: space-between;
 }
-
-#controls a {
-    width: 40px;
-    margin-left: -20px;
-}
diff --git a/web/skins/classic/css/classic/views/frame.css b/web/skins/classic/css/classic/views/frame.css
index c9cb1846c..947fee1bc 100644
--- a/web/skins/classic/css/classic/views/frame.css
+++ b/web/skins/classic/css/classic/views/frame.css
@@ -9,8 +9,3 @@
     display: flex;
     justify-content: space-between;
 }
-
-#controls a {
-    width: 40px;
-    margin-left: -20px;
-}
diff --git a/web/skins/classic/css/dark/views/frame.css b/web/skins/classic/css/dark/views/frame.css
index c9cb1846c..947fee1bc 100644
--- a/web/skins/classic/css/dark/views/frame.css
+++ b/web/skins/classic/css/dark/views/frame.css
@@ -9,8 +9,3 @@
     display: flex;
     justify-content: space-between;
 }
-
-#controls a {
-    width: 40px;
-    margin-left: -20px;
-}
diff --git a/web/skins/classic/views/frame.php b/web/skins/classic/views/frame.php
index 931951056..ae69fecba 100644
--- a/web/skins/classic/views/frame.php
+++ b/web/skins/classic/views/frame.php
@@ -51,14 +51,15 @@ $lastFid = $maxFid;
 $alarmFrame = $Frame->Type()=='Alarm';
 
 if ( isset( $_REQUEST['scale'] ) ) {
-  $scale = $_REQUEST['scale'];
+  $scale = validNum($_REQUEST['scale']);
 } else if ( isset( $_COOKIE['zmWatchScale'.$Monitor->Id()] ) ) {
-  $scale = $_COOKIE['zmWatchScale'.$Monitor->Id()];
+  $scale = validNum($_COOKIE['zmWatchScale'.$Monitor->Id()]);
 } else if ( isset( $_COOKIE['zmWatchScale'] ) ) {
-  $scale = $_COOKIE['zmWatchScale'];
+  $scale = validNum($_COOKIE['zmWatchScale']);
 } else {
   $scale = max( reScale( SCALE_BASE, $Monitor->DefaultScale(), ZM_WEB_DEFAULT_SCALE ), SCALE_BASE );
 }
+$scale = $scale ?: "auto";
 
 $imageData = $Event->getImageSrc( $frame, $scale, 0 );
 if ( ! $imageData ) {
@@ -67,7 +68,7 @@ if ( ! $imageData ) {
 }
 
 $show = 'capt';
-if ( isset($_REQUEST['show']) ) {
+if (isset($_REQUEST['show']) && in_array($_REQUEST['show'], array('capt', 'anal'))) {
   $show = $_REQUEST['show'];
 } else if ( $imageData['hasAnalImage'] ) {
   $show = 'anal';
@@ -89,9 +90,9 @@ xhtmlHeaders(__FILE__, translate('Frame').' - '.$Event->Id()." - ".$Frame->Frame
       <div id="headerButtons">
         <?php if ( ZM_RECORD_EVENT_STATS && $alarmFrame ) { echo makePopupLink( '?view=stats&amp;eid='.$Event->Id().'&amp;fid='.$Frame->FrameId(), 'zmStats', 'stats', translate('Stats') ); } ?>
         <?php if ( canEdit( 'Events' ) ) { ?><a href="?view=none&amp;action=delete&amp;markEid=<?php echo $Event->Id() ?>"><?php echo translate('Delete') ?></a><?php } ?>
-        <a href="#" onclick="closeWindow(); return( false );"><?php echo translate('Close') ?></a>
+        <a href="#" data-on-click="closeWindow"><?php echo translate('Close') ?></a>
       </div>
-      <div id="scaleControl"><label for="scale"><?php echo translate('Scale') ?></label><?php echo buildSelect('scale', $scales, 'changeScale();'); ?></div>
+      <div id="scaleControl"><label for="scale"><?php echo translate('Scale') ?></label><?php echo buildSelect('scale', $scales); ?></div>
       <h2><?php echo translate('Frame') ?> <?php echo $Event->Id().'-'.$Frame->FrameId().' ('.$Frame->Score().')' ?></h2>
       <input type="hidden" name="base_width" id="base_width" value="<?php echo $Event->Width(); ?>"/>
       <input type="hidden" name="base_height" id="base_height" value="<?php echo $Event->Height(); ?>"/>
@@ -103,19 +104,19 @@ xhtmlHeaders(__FILE__, translate('Frame').' - '.$Event->Id()." - ".$Frame->Frame
 <?php if ( $imageData['hasAnalImage'] ) {
  echo sprintf('<a href="?view=frame&amp;eid=%d&amp;fid=%d&scale=%d&amp;show=%s">', $Event->Id(), $Frame->FrameId(), $scale, ( $show=='anal'?'capt':'anal' ) );
 } ?>
-<img id="frameImg" src="<?php echo $Frame->getImageSrc($show=='anal'?'analyse':'capture') ?>" width="<?php echo reScale( $Event->Width(), $Event->DefaultScale(), $scale ) ?>" height="<?php echo reScale( $Event->Height(), $Event->DefaultScale(), $scale ) ?>" alt="<?php echo $Frame->EventId()."-".$Frame->FrameId() ?>" class="<?php echo $imageData['imageClass'] ?>"/>
+<img id="frameImg" src="<?php echo validHtmlStr($Frame->getImageSrc($show=='anal'?'analyse':'capture')) ?>" width="<?php echo reScale( $Event->Width(), $Event->DefaultScale(), $scale ) ?>" height="<?php echo reScale( $Event->Height(), $Event->DefaultScale(), $scale ) ?>" alt="<?php echo $Frame->EventId()."-".$Frame->FrameId() ?>" class="<?php echo $imageData['imageClass'] ?>"/>
 <?php if ( $imageData['hasAnalImage'] ) { ?></a><?php } ?>
 
       </p>
       <p id="controls">
 <?php if ( $Frame->FrameId() > 1 ) { ?>
-        <button type="button" id="firstLink" onclick="window.location='?view=frame&amp;eid=<?php echo $Event->Id() ?>&amp;fid=<?php echo $firstFid ?>&amp;scale=<?php echo $scale ?>&amp;show=<?php echo $show ?>';"><?php echo translate('First') ?></button>
-        <button type="button" id="prevLink" onclick="window.location='?view=frame&amp;eid=<?php echo $Event->Id() ?>&amp;fid=<?php echo $prevFid ?>&amp;scale=<?php echo $scale ?>&amp;show=<?php echo $show ?>';"><?php echo translate('Prev') ?></button>
+        <a class="btn-primary" id="firstLink" href="?view=frame&amp;eid=<?php echo $Event->Id() ?>&amp;fid=<?php echo $firstFid ?>&amp;scale=<?php echo $scale ?>&amp;show=<?php echo $show ?>"><?php echo translate('First') ?></a>
+        <a class="btn-primary" id="prevLink" href="?view=frame&amp;eid=<?php echo $Event->Id() ?>&amp;fid=<?php echo $prevFid ?>&amp;scale=<?php echo $scale ?>&amp;show=<?php echo $show ?>"><?php echo translate('Prev') ?></a>
 <?php
       }
       if ( $Frame->FrameId() < $maxFid ) { ?>
-        <button type="button" id="nextLink" onclick="window.location='?view=frame&amp;eid=<?php echo $Event->Id() ?>&amp;fid=<?php echo $nextFid ?>&amp;scale=<?php echo $scale ?>&amp;show=<?php echo $show ?>';"><?php echo translate('Next') ?></button>
-        <button type="button" id="lastLink" onclick="window.location='?view=frame&amp;eid=<?php echo $Event->Id() ?>&amp;fid=<?php echo $lastFid ?>&amp;scale=<?php echo $scale ?>&amp;show=<?php echo $show ?>';"><?php echo translate('Last') ?></button>
+        <a class="btn-primary" id="nextLink" href="?view=frame&amp;eid=<?php echo $Event->Id() ?>&amp;fid=<?php echo $nextFid ?>&amp;scale=<?php echo $scale ?>&amp;show=<?php echo $show ?>"><?php echo translate('Next') ?></a>
+        <a class="btn-primary" id="lastLink" href="?view=frame&amp;eid=<?php echo $Event->Id() ?>&amp;fid=<?php echo $lastFid ?>&amp;scale=<?php echo $scale ?>&amp;show=<?php echo $show ?>"><?php echo translate('Last') ?></a>
 <?php } ?>
       </p>
 <?php if (file_exists ($dImagePath)) { ?>
diff --git a/web/skins/classic/views/js/frame.js b/web/skins/classic/views/js/frame.js
index e0401c7c7..03058ff8a 100644
--- a/web/skins/classic/views/js/frame.js
+++ b/web/skins/classic/views/js/frame.js
@@ -30,4 +30,10 @@ function changeScale() {
   });
 }
 
-if (scale == 'auto') $j(document).ready(changeScale);
+if (scale == 'auto') {
+  $j(document).ready(changeScale);
+}
+
+document.addEventListener('DOMContentLoaded', function onDCL() {
+  document.getElementById('scale').addEventListener('change', changeScale);
+});
diff --git a/web/skins/classic/views/js/frame.js.php b/web/skins/classic/views/js/frame.js.php
index c9b3f2eea..572587f82 100644
--- a/web/skins/classic/views/js/frame.js.php
+++ b/web/skins/classic/views/js/frame.js.php
@@ -1,3 +1,3 @@
-var scale = '<?php echo $scale ?>';
+var scale = '<?php echo validJsStr($scale); ?>';
 
 var SCALE_BASE = <?php echo SCALE_BASE ?>;