How to add async tag to script in Wordpress #php

async_script_wordpress.php

///in functions.php

<?php
function add_async_attribute($tag, $handle) {
    if ( 'SCRIPT_NAME' !== $handle )
        return $tag;
    return str_replace( ' src', ' async src', $tag );
}
add_filter('script_loader_tag', 'add_async_attribute', 10, 2);