У вашего броузера проблема в совместимости с HTML5
This video goes over how to implement the custom logo support in a WordPress theme. The allows the the theme user to upload a logo in the WordPress Customizer. The video also goes over how to check if the logo is present and if it isn’t to just display the blog name.
View the code here: https://helpwp.com/how-to-add-custom-logo-support-to-wordpress-theme/