Snippet to add the page number to a reveal.js presentation. (Does not add a number to the first slide!)

gistfile1.html

<script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
<script>
function currentPageFormatter(event) {
        var formattedStr;
        
        if (event.indexh === 0) {
                return "";
        }

        formattedStr = event.indexh;

        if (event.indexv) {
            formattedStr += "/" + event.indexv;
        }

        return formattedStr;
    }

    Reveal.addEventListener( 'ready', function( event ) {
        $('<aside class="controls slide-number" style="display: block; left: 10px; right: initial;bottom: -30px; text-align: center;"></aside>')
            .text(currentPageFormatter(event))
            .appendTo('.reveal.center');
    } );

    // Fires each time a new slide is activated
    Reveal.addEventListener( 'slidechanged', function( event ) {
        // event.previousSlide, event.currentSlide, event.indexh, event.indexv
        $(".slide-number").text(currentPageFormatter(event));
    } );
</script>