Highcharts local save

HTML

<script src="http://code.highcharts.com/highcharts.js"></script>
<script src="http://code.highcharts.com/modules/exporting.js"></script>
<script src="http://canvg.googlecode.com/svn/trunk/rgbcolor.js"></script>
<script src="http://canvg.googlecode.com/svn/trunk/canvg.js"></script>
<div id="container" style="min-width: 300px; height: 300px; margin: 2em"></div>

JavaScript

/**
 * This method gets the SVG of the chart and uses canvg to draw it on a HTML5 canvas.
 * The canvas is then streamed to the browser window as a download.
 */
$(function (H) {
    H.Chart.prototype.createCanvas = function (divId) {
        var svg = this.getSVG(),
            width = parseInt(svg.match(/width="([0-9]+)"/)[1]),
            height = parseInt(svg.match(/height="([0-9]+)"/)[1]),
            canvas = document.createElement('canvas');

        canvas.setAttribute('width', width);
        canvas.setAttribute('height', height);

        if (canvas.getContext && canvas.getContext('2d')) {

            canvg(canvas, svg);

            var image = canvas.toDataURL("image/png")
                .replace("image/png", "image/octet-stream");

            // Save locally
            window.location.href = image;
        } 
        else {
            alert("Your browser doesn't support this feature, please use a modern browser");
        }

    }
}(Highcharts));

$('#container').highcharts({

    xAxis: {
        categories: ['01', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
            'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
    },

    title: {
        text: 'Click the button and Save as PNG =>',
        align: 'right',
        x: -40
    },

    series: [{
        data: [29.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4]
    }],

    exporting: {
        buttons: {
            contextButton: {
                menuItems: [{
                    text: 'Print',
                    onclick: function () {
                        this.print();
                    }
                }, {
                    text: 'Save as PNG',
                    onclick: function () {
                        this.createCanvas();
                    },
                    separator: false
                }, {
                    text: 'Save as PDF',
                    onclick: function () {
                        this.exportChart({type: 'application/pdf',...