diff --git a/adminer/include/adminer.inc.php b/adminer/include/adminer.inc.php
index e813164e..8e796e60 100644
--- a/adminer/include/adminer.inc.php
+++ b/adminer/include/adminer.inc.php
@@ -484,7 +484,7 @@ class Adminer {
 		echo "<input type='submit' value='" . lang('Select') . "'>";
 		echo " <span id='noindex' title='" . lang('Full table scan') . "'></span>";
 		echo "<script" . nonce() . ">\n";
-		echo "var indexColumns = ";
+		echo "const indexColumns = ";
 		$columns = array();
 		foreach ($indexes as $index) {
 			$current_key = reset($index["columns"]);
diff --git a/adminer/include/design.inc.php b/adminer/include/design.inc.php
index 5e23ff45..9d67fde3 100644
--- a/adminer/include/design.inc.php
+++ b/adminer/include/design.inc.php
@@ -72,8 +72,8 @@ fQIDAQAB
 		. (isset($_COOKIE["adminer_version"]) ? "" : ", onload: partial(verifyVersion, '$VERSION', '" . js_escape(ME) . "', '" . get_token() . "')") // $token may be empty in auth.inc.php
 		. "});
 document.body.className = document.body.className.replace(/ nojs/, ' js');
-var offlineMessage = '" . js_escape(lang('You are offline.')) . "';
-var thousandsSeparator = '" . js_escape(lang(',')) . "';")
+const offlineMessage = '" . js_escape(lang('You are offline.')) . "';
+const thousandsSeparator = '" . js_escape(lang(',')) . "';")
 	;
 	echo "<div id='help' class='jush-" . JUSH . " jsonly hidden'></div>\n";
 	echo script("mixin(qs('#help'), {onmouseover: function () { helpOpen = 1; }, onmouseout: helpMouseout});");
diff --git a/adminer/include/functions.inc.php b/adminer/include/functions.inc.php
index 62f37ef0..13923016 100644
--- a/adminer/include/functions.inc.php
+++ b/adminer/include/functions.inc.php
@@ -974,7 +974,7 @@ function slow_query($query) {
 	$connection2 = null;
 	if (!$slow_query && support("kill") && is_object($connection2 = connect($adminer->credentials())) && ($db == "" || $connection2->select_db($db))) {
 		$kill = $connection2->result(connection_id()); // MySQL and MySQLi can use thread_id but it's not in PDO_MySQL
-		echo script("var timeout = setTimeout(function () { ajax('" . js_escape(ME) . "script=kill', function () {}, 'kill=$kill&token=$token'); }, 1000 * $timeout);");
+		echo script("const timeout = setTimeout(function () { ajax('" . js_escape(ME) . "script=kill', function () {}, 'kill=$kill&token=$token'); }, 1000 * $timeout);");
 	}
 	ob_flush();
 	flush();
diff --git a/adminer/schema.inc.php b/adminer/schema.inc.php
index d3c74848..34eb7bb1 100644
--- a/adminer/schema.inc.php
+++ b/adminer/schema.inc.php
@@ -53,8 +53,8 @@ foreach (table_status('', true) as $table => $table_status) {
 <div id="schema" style="height: <?php echo $top; ?>em;">
 <script<?php echo nonce(); ?>>
 qs('#schema').onselectstart = function () { return false; };
-var tablePos = {<?php echo implode(",", $table_pos_js) . "\n"; ?>};
-var em = qs('#schema').offsetHeight / <?php echo $top; ?>;
+const tablePos = {<?php echo implode(",", $table_pos_js) . "\n"; ?>};
+const em = qs('#schema').offsetHeight / <?php echo $top; ?>;
 document.onmousemove = schemaMousemove;
 document.onmouseup = partialArg(schemaMouseup, '<?php echo js_escape(DB); ?>');
 </script>
diff --git a/adminer/static/editing.js b/adminer/static/editing.js
index e368bc86..99aa345f 100644
--- a/adminer/static/editing.js
+++ b/adminer/static/editing.js
@@ -396,7 +396,7 @@ function editingMoveRow(up){
 	return false;
 }
 
-var lastType = '';
+let lastType = '';
 
 /** Clear length and hide collation or unsigned
 * @this HTMLSelectElement
diff --git a/plugins/tables-filter.php b/plugins/tables-filter.php
index 92e04112..97334602 100644
--- a/plugins/tables-filter.php
+++ b/plugins/tables-filter.php
@@ -10,8 +10,8 @@ class AdminerTablesFilter {
 	function tablesPrint($tables) {
 		?>
 <script<?php echo Adminer\nonce(); ?>>
-var tablesFilterTimeout = null;
-var tablesFilterValue = '';
+let tablesFilterTimeout = null;
+let tablesFilterValue = '';
 
 function tablesFilter() {
 	const value = qs('#filter-field').value.toLowerCase();