$('#donationvalue').on('input change', function() {
    var vals = [1, 2, 5, 10, 15, 20, 25, 30, 50, 100];
    var val = $('#donationvalue').val();
    var rval = parseInt(val, 10) + 1;
    $('#donationoutput').text(vals[val]);
    $('#donationicons span').removeClass('selected');
    $('#donationicons span:nth-of-type(' + rval + ')').addClass('selected');
});

$('#donationicons span').click(function() {
    var val = $('#donationicons span').index(this) / 2;
    $('#donationvalue').val(val);
    $('#donationvalue').change();
});