Merge branch '3.1' into 5.2

diff --cc wcfsetup/install/files/lib/util/StringUtil.class.php
index 10e187e60c22065243565e990d533bbf7e4db3b5,df7655c85fb2b9887d8b73c48d53cb83039a2330..af3134ff502ecd9b3c4698bb7338b84f63eac6c4
--- 1/wcfsetup/install/files/lib/util/StringUtil.class.php
--- 2/wcfsetup/install/files/lib/util/StringUtil.class.php
+++ b/wcfsetup/install/files/lib/util/StringUtil.class.php
@@@ -119,8 -105,23 +119,8 @@@ final class StringUtil 
         * @return      string
         */
        public static function encodeJS($string) {
 -              // unify newlines
                $string = self::unifyNewlines($string);
-               $string = str_replace(["\\", "'", "\n", "/"], ["\\\\", "\'", '\n', '\/'], $string);
 -              
 -              // escape backslash
 -              $string = str_replace("\\", "\\\\", $string);
 -              
 -              // escape singe quote
 -              $string = str_replace("'", "\'", $string);
 -              
 -              // escape double quote
 -              $string = str_replace('"', '\"', $string);
 -              
 -              // escape new lines
 -              $string = str_replace("\n", '\n', $string);
 -              
 -              // escape slashes
 -              $string = str_replace("/", '\/', $string);
++              $string = str_replace(["\\", "'", '"', "\n", "/"], ["\\\\", "\'", '\"', '\n', '\/'], $string);
                
                return $string;
        }