var signingIn = false;

$(document).ready(function() {
    $('button#signbtn').click(function() {
        if (!signingIn) {
            signingIn = true;

            var img = $('<img id="loader" style="padding-left: 10px;" src="loader.gif"/>');
            $(this).after(img);

            $.ajax({
                url: '/logs',
                type: 'post',
                data: $('form#signform').serialize();,
                success: function() {
                    $('img#loader').remove();
                    alert('success');
                }
            });
        }
        return false;
    });
});