img_support.js

/*! img_support.js v1.0.0 | github.com/MoisesKMS/img_support */
(function (document) {
    var formats = {
        avif: "image/avif",
        webp: "image/webp",
    };

    function setHTMLClass(format, supported) {
        if (supported) {
            document.documentElement.classList.add(format);
        } else {
            document.documentElement.classList.add("not" + format);
        }
    }

    function checkImageFormat(format) {
        var image = new Image();
        image.onload = image.onerror = function () {
            setHTMLClass(format, image.height === 2);
        };
        image.src = "data:" + formats[format] + ";base64," + getImageData(format);
    }

    function getImageData(format) {
        return {
            avif: "AAAAIGZ0eXBhdmlmAAAAAGF2aWZtaWYxbWlhZk1BMUIAAADybWV0YQAAAAAAAAAoaGRscgAAAAAAAAAAcGljdAAAAAAAAAAAAAAAAGxpYmF2aWYAAAAADnBpdG0AAAAAAAEAAAAeaWxvYwAAAABEAAABAAEAAAABAAABGgAAAB0AAAAoaWluZgAAAAAAAQAAABppbmZlAgAAAAABAABhdjAxQ29sb3IAAAAAamlwcnAAAABLaXBjbwAAABRpc3BlAAAAAAAAAAIAAAACAAAAEHBpeGkAAAAAAwgICAAAAAxhdjFDgQ0MAAAAABNjb2xybmNseAACAAIAAYAAAAAXaXBtYQAAAAAAAAABAAEEAQKDBAAAACVtZGF0EgAKCBgANogQEAwgMg8f8D///8WfhwB8+ErK42A=",
            webp: "UklGRjoAAABXRUJQVlA4IC4AAACyAgCdASoCAAIALmk0mk0iIiIiIgBoSygABc6WWgAA/veff/0PP8bA//LwYAAA",
        }[format];
    }

    for (var format in formats) {
        checkImageFormat(format);
    }
})(
    (window.sandboxApi &&
        window.sandboxApi.parentWindow &&
        window.sandboxApi.parentWindow.document) ||
    document
);