66 lines
2.0 KiB
Markdown
66 lines
2.0 KiB
Markdown
# Usage
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Chart.js can be used with ES6 modules, plain JavaScript and module loaders.
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## Creating a Chart
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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.
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```html
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<canvas id="myChart" width="400" height="400"></canvas>
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```
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```javascript
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// Any of the following formats may be used
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var ctx = document.getElementById('myChart');
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var ctx = document.getElementById('myChart').getContext('2d');
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var ctx = $('#myChart');
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var ctx = 'myChart';
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```
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Once you have the element or context, you're ready to instantiate a pre-defined chart-type or create your own!
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The following example instantiates a bar chart showing the number of votes for different colors and the y-axis starting at 0.
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```html
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<canvas id="myChart" width="400" height="400"></canvas>
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<script>
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var ctx = document.getElementById('myChart');
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var myChart = new Chart(ctx, {
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type: 'bar',
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data: {
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labels: ['Red', 'Blue', 'Yellow', 'Green', 'Purple', 'Orange'],
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datasets: [{
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label: '# of Votes',
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data: [12, 19, 3, 5, 2, 3],
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backgroundColor: [
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'rgba(255, 99, 132, 0.2)',
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'rgba(54, 162, 235, 0.2)',
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'rgba(255, 206, 86, 0.2)',
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'rgba(75, 192, 192, 0.2)',
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'rgba(153, 102, 255, 0.2)',
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'rgba(255, 159, 64, 0.2)'
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],
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borderColor: [
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'rgba(255, 99, 132, 1)',
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'rgba(54, 162, 235, 1)',
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'rgba(255, 206, 86, 1)',
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'rgba(75, 192, 192, 1)',
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'rgba(153, 102, 255, 1)',
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'rgba(255, 159, 64, 1)'
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],
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borderWidth: 1
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}]
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},
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options: {
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scales: {
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yAxes: [{
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ticks: {
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beginAtZero: true
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}
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}]
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}
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}
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});
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</script>
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```
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