For Chart.js 2.x refer to andyhasit's answer - https://stackoverflow.com/a/36954319/360067
For Chart.js 1.x, you can tweak the options and extend the chart type to do this, like so
Chart.types.Line.extend({
name: "LineAlt",
draw: function () {
Chart.types.Line.prototype.draw.apply(this, arguments);
var ctx = this.chart.ctx;
ctx.save();
// text alignment and color
ctx.textAlign = "center";
ctx.textBaseline = "bottom";
ctx.fillStyle = this.options.scaleFontColor;
// position
var x = this.scale.xScalePaddingLeft * 0.4;
var y = this.chart.height / 2;
// change origin
ctx.translate(x, y);
// rotate text
ctx.rotate(-90 * Math.PI / 180);
ctx.fillText(this.datasets[0].label, 0, 0);
ctx.restore();
}
});
calling it like this
var ctx = document.getElementById("myChart").getContext("2d");
var myLineChart = new Chart(ctx).LineAlt(data, {
// make enough space on the right side of the graph
scaleLabel: " <%=value%>"
});
Notice the space preceding the label value, this gives us space to write the y axis label without messing around with too much of Chart.js internals
Fiddle - http://jsfiddle.net/wyox23ga/
