d3.js Getting started with d3.js Simple D3 Chart: Hello World!
Example
Paste this code into an empty HTML file and run it in your browser.
<!DOCTYPE html>
<body>
<script src="https://d3js.org/d3.v4.js"></script> <!-- This downloads d3 library -->
<script>
//This code will visualize a data set as a simple scatter chart using d3. I omit axes for simplicity.
var data = [ //This is the data we want to visualize.
//In reality it usually comes from a file or database.
{x: 10, y: 10},
{x: 10, y: 20},
{x: 10, y: 30},
{x: 10, y: 40},
{x: 10, y: 50},
{x: 10, y: 80},
{x: 10, y: 90},
{x: 10, y: 100},
{x: 10, y: 110},
{x: 20, y: 30},
{x: 20, y: 120},
{x: 30, y: 10},
{x: 30, y: 20},
{x: 30, y: 30},
{x: 30, y: 40},
{x: 30, y: 50},
{x: 30, y: 80},
{x: 30, y: 90},
{x: 30, y: 100},
{x: 30, y: 110},
{x: 40, y: 120},
{x: 50, y: 10},
{x: 50, y: 20},
{x: 50, y: 30},
{x: 50, y: 40},
{x: 50, y: 50},
{x: 50, y: 80},
{x: 50, y: 90},
{x: 50, y: 100},
{x: 50, y: 110},
{x: 60, y: 10},
{x: 60, y: 30},
{x: 60, y: 50},
{x: 70, y: 10},
{x: 70, y: 30},
{x: 70, y: 50},
{x: 70, y: 90},
{x: 70, y: 100},
{x: 70, y: 110},
{x: 80, y: 80},
{x: 80, y: 120},
{x: 90, y: 10},
{x: 90, y: 20},
{x: 90, y: 30},
{x: 90, y: 40},
{x: 90, y: 50},
{x: 90, y: 80},
{x: 90, y: 120},
{x: 100, y: 50},
{x: 100, y: 90},
{x: 100, y: 100},
{x: 100, y: 110},
{x: 110, y: 50},
{x: 120, y: 80},
{x: 120, y: 90},
{x: 120, y: 100},
{x: 120, y: 110},
{x: 120, y: 120},
{x: 130, y: 10},
{x: 130, y: 20},
{x: 130, y: 30},
{x: 130, y: 40},
{x: 130, y: 50},
{x: 130, y: 80},
{x: 130, y: 100},
{x: 140, y: 50},
{x: 140, y: 80},
{x: 140, y: 100},
{x: 140, y: 110},
{x: 150, y: 50},
{x: 150, y: 90},
{x: 150, y: 120},
{x: 170, y: 20},
{x: 170, y: 30},
{x: 170, y: 40},
{x: 170, y: 80},
{x: 170, y: 90},
{x: 170, y: 100},
{x: 170, y: 110},
{x: 170, y: 120},
{x: 180, y: 10},
{x: 180, y: 50},
{x: 180, y: 120},
{x: 190, y: 10},
{x: 190, y: 50},
{x: 190, y: 120},
{x: 200, y: 20},
{x: 200, y: 30},
{x: 200, y: 40},
{x: 210, y: 80},
{x: 210, y: 90},
{x: 210, y: 100},
{x: 210, y: 110},
{x: 210, y: 120},
{x: 220, y: 80},
{x: 220, y: 120},
{x: 230, y: 80},
{x: 230, y: 120},
{x: 240, y: 90},
{x: 240, y: 100},
{x: 240, y: 110},
{x: 270, y: 70},
{x: 270, y: 80},
{x: 270, y: 90},
{x: 270, y: 100},
{x: 270, y: 120}
];
//The following code chains a bunch of methods. Method chaining is what makes d3 very simple and concise.
d3.select("body").append("svg").selectAll() //'d3' calls the d3 library
//'.select' selects the object (in this case the body of HTML)
//'.append' adds SVG element to the body
//'.selectAll()' selects all SVG elements
.data(data) //'.data' gets the data from the variable 'data'
.enter().append("circle") //'.enter' enters the data into the SVG
//the data enter as circles with '.append("circle")'
.attr("r", 3) //'.attr' adds/alters atributes of SVG,
//such as radius ("r"), making it 3 pixels
.attr("cx", function(d) { return d.x; }) //coordinates "cx" (circles' x coordinates)
.attr("cy", function(d) { return d.y; }) //coordinates "cy" (circles' y coordinates)
.style("fill", "darkblue"); //'.style' changes CSS of the SVG
//in this case, fills circles with "darkblue" color
</script>
Here is a JSFiddle of the chart.
You can also download the already created HTML file from GitHub.
The next step in learning d3 can be following Mike Bostock's (the d3's creator's) tutorial to create a bar chart from scratch.
