What Is a Function?
A function is a reusable block of code.
What Is a Function? is a free Javascript for Kids lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Javascript for Kids learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
A Magic Spell! 🪄
Imagine you are a wizard. 🧙 A function is like a magic spell you can use again and again!
You write the spell once, then say its name whenever you want it to happen. ✨
Why Spells Are Cool 😎
Pretend you want to say "Hello!" ten times.
Instead of typing it ten times, you put it in a spell. Then you just cast the spell! 🎉
A Spell That Says Hi 👋
Here is a tiny spell. It says hi when we use it. Press Run and watch! 🟢
function sayHi() {
console.log("Hi, friend!");
}
sayHi();The Two Parts 🧩
A spell has two parts:
- Making the spell (writing it down) 📝
- Using the spell (casting it!) 🪄
We made sayHi, then we used sayHi().
The Magic Word 🔑
The word function tells the computer: "A spell is coming!" 🐉
Then we give the spell a name, like sayHi. Names help us find our spell later.
Curly Braces Hold the Magic ✨
The { } curly braces are like a treasure chest. 🧰
Everything inside the chest is the magic that happens when we cast the spell!
function cheer() {
console.log("Hooray!");
console.log("You did it!");
}
cheer();Cast It Many Times! 🔁
The best part: you can cast a spell as many times as you want! 🎆
function bark() {
console.log("Woof woof!");
}
bark();
bark();
bark();Spells Save Time ⏱️
If you change the spell once, it changes everywhere you use it. So smart! 🧠
No need to fix the same thing over and over. Wizards are lazy in a good way! 😄
Naming Your Spell 🏷️
Pick fun names that say what the spell does, like danceParty or feedCat. 🐱
Good names make your magic easy to read!
function danceParty() {
console.log("Wiggle wiggle!");
}
danceParty();Empty Until You Cast 🫥
Writing a spell does nothing on its own. It just waits. 😴
Only when you cast it with () does the magic happen! 🌟
You Are a Code Wizard! 🧙♂️
You now know that a function is a reusable spell. Make it once, cast it lots! ✨
Soon you will make your very own spells!
Quick Check 🧠
Time for a fun question! 🎯
You Are a Star! ⭐
Awesome work! A function is a spell you write once and use lots. 🎉
Next, you will write your very first spell. Get ready! 🚀
Frequently asked questions
Is the “What Is a Function?” lesson free?
Yes — the full text of “What Is a Function?” is free to read here on the web, and the Javascript for Kids course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Javascript for Kids course, upgrade to CoddyKit PRO.
What will I learn in “What Is a Function?”?
A function is a reusable block of code. You practise Javascript for Kids with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Javascript for Kids?
No prior experience is required. Javascript for Kids on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “What Is a Function?” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Javascript for Kids lesson?
Yes. Every Javascript for Kids lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- What Is a Function?
- Making Your First Function
- Giving Functions Information
- Getting Answers Back