    public function addElementToContentSet($element, $type) {
        if (!isset($this->content_sets[$type])) $this->content_sets[$type] = '';
        else $this->content_sets[$type] .= ' | ';
        $this->content_sets[$type] .= $element;
    }
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.