diff --git a/ChangeLog b/ChangeLog
index c77cb68bec..08adffc295 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,7 @@ phpMyAdmin - ChangeLog
 
 4.2.9.0 (not yet released)
 - bug       ajax.js responseHandler: cannot read property of null
+- bug       sql.js: str is undefined
 
 4.2.8.0 (2014-08-31)
 - bug #4516 Odd export behavior
diff --git a/js/sql.js b/js/sql.js
index aa4ca3b346..d16e982032 100644
--- a/js/sql.js
+++ b/js/sql.js
@@ -18,7 +18,9 @@ var prevScrollX = 0, fixedTop;
  */
 function PMA_urldecode(str)
 {
-    return decodeURIComponent(str.replace(/\+/g, '%20'));
+    if (typeof str !== 'undefined') {
+        return decodeURIComponent(str.replace(/\+/g, '%20'));
+    }
 }
 
 /**
@@ -29,7 +31,9 @@ function PMA_urldecode(str)
  */
 function PMA_urlencode(str)
 {
-    return encodeURIComponent(str).replace(/\%20/g, '+');
+    if (typeof str !== 'undefined') {
+        return encodeURIComponent(str).replace(/\%20/g, '+');
+    }
 }
 
 /**