diff --git a/adminer/schema.inc.php b/adminer/schema.inc.php
index f71441c3..a60d4529 100644
--- a/adminer/schema.inc.php
+++ b/adminer/schema.inc.php
@@ -51,8 +51,8 @@ foreach (table_status() as $table_status) {
 ?>
 <div id="schema" style="height: <?php echo $top; ?>em;" onselectstart="return false;">
 <script type="text/javascript">
-tablePos = {<?php echo implode(",", $table_pos_js) . "\n"; ?>};
-em = document.getElementById('schema').offsetHeight / <?php echo $top; ?>;
+var tablePos = {<?php echo implode(",", $table_pos_js) . "\n"; ?>};
+var em = document.getElementById('schema').offsetHeight / <?php echo $top; ?>;
 document.onmousemove = schemaMousemove;
 document.onmouseup = function (ev) {
 	schemaMouseup(ev, '<?php echo js_escape(DB); ?>');
diff --git a/adminer/static/editing.js b/adminer/static/editing.js
index a1bdf4d3..ec79efec 100644
--- a/adminer/static/editing.js
+++ b/adminer/static/editing.js
@@ -393,7 +393,7 @@ function indexesAddColumn(field, prefix) {
 
 
 
-var that, x, y, em, tablePos;
+var that, x, y; // em and tablePos defined in schema.inc.php
 
 /** Get mouse position
 * @param HTMLElement