Chart.js - W3Schools

Chart.js ❮ Previous Next ❯

Chart.js is a free JavaScript library for making HTML-based charts. It is one of the simplest visualization libraries for JavaScript, and comes with the following built-in chart types:

• Scatter Plot
• Line Chart
• Bar Chart
• Pie Chart
• Donut Chart
• Bubble Chart
• Area Chart
• Radar Chart
• Mixed Chart

How to Use Chart.js?

Chart.js is easy to use.

First, add a link to the providing CDN (Content Delivery Network):

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"> </script>

Then, add a <canvas> to where you want to draw the chart:

<canvas id="myChart" style="width:100%;max-width:700px"></canvas>

The canvas element must have a unique id.

That's all!

Typical Scatter Chart Syntax:

const myChart = new Chart("myChart", { type: "scatter", data: {}, options: {} });

Typical Line Chart Syntax:

const myChart = new Chart("myChart", { type: "line", data: {}, options: {} });

Typical Bar Chart Syntax:

const myChart = new Chart("myChart", { type: "bar", data: {}, options: {} });

Scatter Plots

House Prices vs. Size

Source Code

const xyValues = [ {x:50, y:7}, {x:60, y:8}, {x:70, y:8}, {x:80, y:9}, {x:90, y:9}, {x:100, y:9}, {x:110, y:10}, {x:120, y:11}, {x:130, y:14}, {x:140, y:14}, {x:150, y:15} ]; new Chart("myChart", { type: "scatter", data: { datasets: [{ pointRadius: 4, pointBackgroundColor: "rgba(0,0,255,1)", data: xyValues }] }, options:{...} });

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Line Graphs

House Prices vs. Size

Source Code

const xValues = [50,60,70,80,90,100,110,120,130,140,150]; const yValues = [7,8,8,9,9,9,10,11,14,14,15]; new Chart("myChart", { type: "line", data: { labels: xValues, datasets: [{ backgroundColor:"rgba(0,0,255,1.0)", borderColor: "rgba(0,0,255,0.1)", data: yValues }] }, options:{...} });

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If you set the borderColor to zero, you can scatter plot the line graph:

borderColor: "rgba(0,0,0,0)",

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Multiple Lines

Source Code

const xValues = [100,200,300,400,500,600,700,800,900,1000]; new Chart("myChart", { type: "line", data: { labels: xValues, datasets: [{ data: [860,1140,1060,1060,1070,1110,1330,2210,7830,2478], borderColor: "red", fill: false },{ data: [1600,1700,1700,1900,2000,2700,4000,5000,6000,7000], borderColor: "green", fill: false },{ data: [300,700,2000,5000,6000,4000,2000,1000,200,100], borderColor: "blue", fill: false }] }, options: { legend: {display: false} } });

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Linear Graphs

Source Code

const xValues = []; const yValues = []; generateData("x * 2 + 7", 0, 10, 0.5); new Chart("myChart", { type: "line", data: { labels: xValues, datasets: [{ fill: false, pointRadius: 1, borderColor: "rgba(255,0,0,0.5)", data: yValues }] }, options: {...} }); function generateData(value, i1, i2, step = 1) { for (let x = i1; x