Insert <canvas> with wp_footer hook

Using wp_footer hook to add a <canva> element to the page is printing <canvas class="my_canvas"> instead of <canvas class="my_canvas"></canvas>

Here is the hook:

if (!function_exists('add_canvas')) {
    function add_canvas()
    {
        echo '<canvas class="my_canvas"></canvas>';
    }
}
add_action('wp_footer', 'add_canvas', 100);