1var bar = new ProgressBar.Line('#container', {
2    step: function(state, bar, attachment) {
3        bar.path.setAttribute('stroke', state.color);
4    }
5});
6
7var opts = {
8    from: { color: '#000 '},
9    to: { color: '#888'}
10};
11bar.animate(0.5, opts);
12