Chart.js
Chart.js is a free JavaScript library for creating HTML-based charts. It is one of the simplest visualization libraries and comes with many built-in chart types, including:
- Scatter Plot
- Line Chart
- Bar Chart
- Pie Chart
- Donut Chart
- Bubble Chart
- Area Chart
- Radar Chart
- Mixed Chart
How to Use Chart.js
- Add a link to the Chart.js CDN:
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
Add a <canvas> element to your HTML where you want to draw the chart:
<canvas id="myChart" style="width:100%;max-width:700px"></canvas>
Typical Syntax
Bar Chart:
const myChart = new Chart("myChart", { type: "bar", data: {}, options: {}});
Line Chart:
const myChart = new Chart("myChart", { type: "line", data: {}, options: {}});
Bar Charts
Source Code:
const xValues = ["Italy", "France", "Spain", "USA", "Argentina"];
const yValues = [55, 49, 44, 24, 15];
const barColors = ["red", "green", "blue", "orange", "brown"];
new Chart("myChart", {
type: "bar",
data: {
labels: xValues,
datasets: [{
backgroundColor: barColors,
data: yValues
}]
},
options: {...}
});
Horizontal Bar Chart:
type: "horizontalBar",
Pie Charts
Example:
new Chart("myChart", {
type: "pie",
data: {
labels: xValues,
datasets: [{
backgroundColor: barColors,
data: yValues
}]
},
options: {
title: {
display: true,
text: "World Wide Wine Production"
}
}
});
Doughnut Charts
Example:
type: "doughnut",
Scatter Plots
House Prices vs. Size:
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: {...}
});
Line Graphs
House Prices vs. Size:
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: {...}
});
Multiple Lines:
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}
}
});
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 <= i2; x += step) {
yValues.push(eval(value));
xValues.push(x);
}
}
Function Graphs:
generateData("Math.sin(x)", 0, 10, 0.5);