1.4 KiB
Hello, JavaScript!
The programs in JavaScript are called scripts. They can be embedded right into HTML using <script> tag and run automatically as the page loads.
For example, this HTML-page shows the "Hello" message:
<!doctype html>
<script>
alert("Hello, world!");
</script>
JavaScript can execute not only in a browser, but also on a server, or actually on any device that has a special program called the JavaScript engine.
Browsers have built-in JavaScript engines, so they can run scripts.
We can also run scripts using Node.js, it's commonly used to build server-side applications.
Depending on the environment, JavaScript may provide platform-specific functionality.
- In a web browser, JavaScript can manipulate the web-page, send network requests, show messages and so on.
- In node.js we can use JavaScript to run a web-server, read and write arbitrary files.
- ...And so on.
Technically, even a coffee machine can include its own JavaScript engine, to allow programming of coffee recipes.
In this tutorial we concentrate on the "core JavaScript", that's the same everywhere.
We'll try to keep browser-specific notes at minimum. After you learn the core, you can go in any direction: browsers, frameworks, servers and so on.
Turn the page to start learning JavaScript!