year.js

(function() {
d3.select(document.body).append('h3').text('Select only Years');
var yearOutput = d3.select(document.body).append('h2');
d3.select(document.body)
    .append('div')
    .call(
      chroniton()
        .domain([new Date('1/1/2000'), new Date('1/1/2015')])
        .width(500)
        .on('change', function(d) {
          yearOutput.text(d3.time.year(d));
        }));
})();