diff --git a/shortcodes/HighlightPhpShortcode.php b/shortcodes/HighlightPhpShortcode.php
index b151ec9..bba7c24 100644
--- a/shortcodes/HighlightPhpShortcode.php
+++ b/shortcodes/HighlightPhpShortcode.php
@@ -17,7 +17,7 @@ public function init()
             $content = $sc->getContent();
             $isInline = is_null($content);
             $code = $isInline ? $sc->getParameter('code') : $content;
-            $code = trim($code, '\n\r');
+            $code = trim($code, "\n\r");
             return $this->render($lang, $code, $isInline);
         });
     }