RGraph is a JavaScript charts library based on HTML5 SVG and canvas. RGraph is mature (over 15 years old) and has a wealth of features making it an ideal choice to use for showing charts on your website.

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Get the latest version of RGraph (version 6.18, 1st June 2024) from the download page. You can read the changelog here. There's also older versions available, minified files and links to cdnjs.com hosted libraries.

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RGraph can be used for free under the GPL or if that doesn't suit your situation there's an inexpensive (£129) commercial license available.

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A Horseshoe chart

[No canvas support]

As mentioned above, this was previously a variant of the Pie chart Now, however, it has been converted to a full chart type - the Horseshoe meter.

It's a small, circular meter-type chart type. In previous incarnations a large amount of code was necessary to create this chart - then less so as a Pie chart variant and now there's similarly only a small amount of code that's necessary to create it. As a full chart type it also supports a better style of the grow effect - so now if the meter is already showing a value and you set a new one and grow to it - instead of always growing from the minimum value the meter will grow from its current value. This is shown in the example here.

The chart is a simple circular meter that has a circle at either end. These circles can be disabled if you wish. The colors of the chart and the label can also be changed.

This goes in the documents header:
<script src="RGraph.common.core.js"></script>
<script src="RGraph.horseshoe.js"></script>
Put this where you want the chart to show up:
<canvas id="cvs" width="300" height="300">[No canvas support]</canvas>
This is the code that generates the chart - it should be placed AFTER the canvas tag(s):
    horseshoe = new RGraph.Horseshoe({
        id: 'cvs',
        min: 0,
        max: 100,
        value: 65,
        options: {
            labelUnitsPost: '%'
    update = function ()
        horseshoe.value = horseshoe.value + RGraph.random(-20,20);
        setTimeout(update, 2000);

    setTimeout(update, 2000);