usage.md

Usage

Chart.js can be used with ES6 modules, plain JavaScript, and module loaders.

Creating a Chart

To create a chart, we need to instantiate the Chart class. To do this, we need to pass in the node, jQuery instance, or 2d context of the canvas of where we want to draw the chart. Here's an example.

<canvas id="myChart" width="400" height="400"></canvas>

// Any of the following formats may be used
const ctx = document.getElementById('myChart');
const ctx = document.getElementById('myChart').getContext('2d');
const ctx = $('#myChart');
const ctx = 'myChart';

Once you have the element or context, you're ready to instantiate a pre-defined chart-type or create your own!

The following example instantiates a bar chart showing the number of votes for different colors and the y-axis starting at 0.

<canvas id="myChart" width="400" height="400"></canvas>
<script>
const ctx = document.getElementById('myChart');
const myChart = new Chart(ctx, {
    type: 'bar',
    data: {
        labels: ['Red', 'Blue', 'Yellow', 'Green', 'Purple', 'Orange'],
        datasets: [{
            label: '# of Votes',
            data: [12, 19, 3, 5, 2, 3],
            backgroundColor: [
                'rgba(255, 99, 132, 0.2)',
                'rgba(54, 162, 235, 0.2)',
                'rgba(255, 206, 86, 0.2)',
                'rgba(75, 192, 192, 0.2)',
                'rgba(153, 102, 255, 0.2)',
                'rgba(255, 159, 64, 0.2)'
            ],
            borderColor: [
                'rgba(255, 99, 132, 1)',
                'rgba(54, 162, 235, 1)',
                'rgba(255, 206, 86, 1)',
                'rgba(75, 192, 192, 1)',
                'rgba(153, 102, 255, 1)',
                'rgba(255, 159, 64, 1)'
            ],
            borderWidth: 1
        }]
    },
    options: {
        scales: {
            y: {
                beginAtZero: true
            }
        }
    }
});
</script>