works in 1.4.2

works in 1.4.2

Am a newbie to jQuery, this works in 1.4.2 but doesnt in 1.9.1
what should I change to make it run

<h1>Long-running request demo</h1>

<div id="progress">Progress not yet initialized</div>

<a href="http://jquery.com/">jQuery</a>
<script src="jquery.js"></script>
<script type="text/javascript">
function pollProgress() {
    $.getJSON('/progress', function(data) {
        if (data.progress === null) {
            return;
        }
        $('#progress').text('progress: ' + data.progress + ' / ' + data.progresslimit);
        setTimeout(pollProgress, 1000);
    });
}

$(document).ready(function() {
    pollProgress();
});
</script>