A Line chart with dynamically updating data

This is a demo of a Line chart that shows a constantly updating Line chart. It updates every 50 milliseconds with new data. There's only one Line chart object and its data is updated (new data added and the last data-piece removed from the datasets) every 50 milliseconds. If you want to change the delay then open the console (CTRL+SHIFT+J in Chrome) and enter: DELAY = 20 and press enter.

This goes in the documents header:
<script src="RGraph.svg.common.core.js"></script>
<script src="RGraph.svg.line.js"></script>
Put this where you want the chart to show up:
<div style="width: 750px; height: 300px" id="chart-container"></div>
This is the code that generates the chart:
<script>
    iteration = 0;
    data      = [];
    last      = 0;
    DELAY     = 50; // Change this to 60000 for a whole days worth of monitoring

    line = new RGraph.SVG.Line({
        id: 'chart-container',
        data: data,
        options: {
            hmargin: 0,
            title: 'An updating SVG Line chart',
            yaxis: false,
            xaxis: false,
            backgroundGridColor: '#ccc',
            backgroundGridVlinesCount: 15,
            backgroundGridBorder: true,
            colors: ['#c00'],
            linewidth: 1,
            yaxisScaleMax: 100
        }
    }).draw();
    
    RGraph.SVG.create({
        svg: line.svg,
        type: 'rect',
        attr: {
            x:35,
            y:35,
            width:680,
            height:230,
            stroke: '#ccc',
            fill: 'transparent'
        }
    });




    function update ()
    {
        if (iteration === 0) {
            line.originalData[0] = RGraph.SVG.arrayFill({
                array:  [],
                length: 1440
            });
        }

        // A global
        last  = last + RGraph.SVG.random({min:-5, max:5});
        if (last < 0)   last = 0;
        if (last > 100) last = 100;

        line.originalData[0].push(last);
        line.originalData[0].shift();

        RGraph.SVG.redraw();
        
        iteration++;

        setTimeout(function ()
        {
            update()
        }, DELAY);
    }

    update();
</script>