diff --git a/lib/formslib.php b/lib/formslib.php
index d64b6190fb7e2..03c8c334e83e6 100644
--- a/lib/formslib.php
+++ b/lib/formslib.php
@@ -1893,7 +1893,7 @@ function qf_errorHandler(element, _qfMsg) {
             list($jsArr,$element)=$jsandelement;
             //end of fix
             $escapedElementName = preg_replace_callback(
-                '/[_\[\]]/',
+                '/[_\[\]-]/',
                 create_function('$matches', 'return sprintf("_%2x",ord($matches[0]));'),
                 $elementName);
             $js .= '