Where Can I JavaScript?

There are lots of places to write and to run JavaScript.

We almost always write JavaScript in our editor (Atom or Sublime).

Running JavaScript in the browser

The first place we see JavaScript running is in the browser. Most web sites you visit use JavaScript to add behaviour or funky interactions to the page. The browser loads an HTML page. Inside there somewhere will be a script tag, probably like this:

<script src="app.js"></script>

Once the browser has downloaded app.js, it executes it.

Running JavaScript in the browser console

Open your browser’s Dev Tools, and select the Console tab. If you’ve used any console.log statements in app.js, this is where they’ll appear.

You can also write and run JavaScript here, like this:

The console returns something every time you hit Enter. You can even console.log here!

Running JavaScript in JS Bin

JS Bin is a web development debugging tool. It’s a bit of a mash up of the insides of a browser and an online editor. It gives you a playground for HTML, CSS, JavaScript, the Console, and the rendered web page Output.

Here you can write JavaScript in the JavaScript tab or in the Console tab, and see the output in the Console tab or the Output tab (depending on what you write).

Now let’s look at Running JavaScript on the command line.