inner_div.className = 'dygraph-axis-label' +
' dygraph-axis-label-' + axis +
(prec_axis ? ' dygraph-axis-label-' + prec_axis : '');
inner_div.className = 'dygraph-axis-label' +
' dygraph-axis-label-' + axis +
(prec_axis ? ' dygraph-axis-label-' + prec_axis : '');