There is a chart instance already initialized on the dom.
时间: 2023-10-19 21:24:42 浏览: 45
If there is a chart instance already initialized on the DOM, you can access it using the chart's ID and the Chart.js library. First, you need to get a reference to the canvas element that contains the chart. You can do this by calling the `getElementById` method on the document object and passing in the ID of the canvas element. Once you have a reference to the canvas element, you can create a new chart instance using the `Chart` constructor and passing in the canvas element and the configuration object for the chart. Here's an example:
```javascript
// Get a reference to the canvas element
var canvas = document.getElementById('myChart');
// Create a new chart instance
var chart = new Chart(canvas, {
type: 'line',
data: {
labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July'],
datasets: [
{
label: 'Sales',
data: [65, 59, 80, 81, 56, 55, 40],
fill: false,
borderColor: 'rgb(75, 192, 192)',
tension: 0.1
}
]
}
});
```
In this example, we're creating a line chart with sales data for several months. The canvas element has an ID of "myChart", so we get a reference to it using `getElementById`. Then we create a new chart instance using the `Chart` constructor and pass in the canvas element and the configuration object for the chart.