pjvandehaar/detect_school.html

## detect_school.html
<html>

<head>
    <script src='http://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js'></script>
    <script>
        function isCached(img_src) {
            var dfd = $.Deferred();
            var start_time = $.now();
            var img;
            var timeout = setTimeout(function() {
                img.off('load');
                img.attr('src', '');
                dfd.resolve(undefined);
            }, 100); //TODO: test failure threshold on slow computers
            img = $('<img style="display:none">')
                .load(function() {
                    clearTimeout(timeout);
                    dfd.resolve($.now() - start_time);
                })
                .attr('src', img_src);
            return dfd.promise();
        }

        var imgs = {
            calvin: "https://portal.calvin.edu/CookieAuth.dll?GetPic?formdir=3&image=portal_logo.png",
            msu: "https://mail.msu.edu/msu_web/_images/wordmark-msu.gif",
            hope: "http://www.hope.edu/sites/all/themes/hope/logo.png",
            mtu: "http://www.mtu.edu/mtu_resources/images/home/home-sprite.png"
        };

        Object.keys(imgs).forEach(function(school) {
            isCached(imgs[school]).done(function(time) {
                $(function() {
                    $('body').append('<pre>' + [time, school, imgs[school]] + '</pre>');
                });
            });
        });
    </script>
</head>

<body>
    <a href='detect_school.html'>Reload without flushing cache</a>
</body>

</html>
	<html>

	<head>
	<script src='http://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js'></script>
	<script>
	function isCached(img_src) {
	var dfd = $.Deferred();
	var start_time = $.now();
	var img;
	var timeout = setTimeout(function() {
	img.off('load');
	img.attr('src', '');
	dfd.resolve(undefined);
	}, 100); //TODO: test failure threshold on slow computers
	img = $('<img style="display:none">')
	.load(function() {
	clearTimeout(timeout);
	dfd.resolve($.now() - start_time);
	})
	.attr('src', img_src);
	return dfd.promise();
	}

	var imgs = {
	calvin: "https://portal.calvin.edu/CookieAuth.dll?GetPic?formdir=3&image=portal_logo.png",
	msu: "https://mail.msu.edu/msu_web/_images/wordmark-msu.gif",
	hope: "http://www.hope.edu/sites/all/themes/hope/logo.png",
	mtu: "http://www.mtu.edu/mtu_resources/images/home/home-sprite.png"
	};

	Object.keys(imgs).forEach(function(school) {
	isCached(imgs[school]).done(function(time) {
	$(function() {
	$('body').append('<pre>' + [time, school, imgs[school]] + '</pre>');
	});
	});
	});
	</script>
	</head>

	<body>
	<a href='detect_school.html'>Reload without flushing cache</a>
	</body>

	</html>