Javascript basics

We include JS code within HTML either by embedding it internally in a script tag:

<script>
console.log("embedded code")
</script>

Or by referencing an external file with the src attribute:

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

And then file.js would contain:

console.log("external code")

When developing client-side (in-browser) apps in Javascript, it’s very important to check on the browser console, part of the developer tools.

• document.getElementById
• document.getElementsByTagName
• document.getElementsByClass
• .nextElementSibling
• .parent
• .children

See jsdemo in the public repository in gitlab for examples.