Lesson 8 of 3324%
(Progress persistence is disabled until Phase 9)
JavaScript
Intermediate
20 min
Loops
Repeat code efficiently.
Learning Objectives
- for and while loops
Loops
Welcome to this lesson on Loops. JavaScript is the programming language of the web, and loops is a fundamental piece of that ecosystem.
Explanation
When your browser loads a web page, the HTML creates the structure, the CSS creates the style, and JavaScript creates the interactivity. JavaScript can update both HTML and CSS in real-time.
Code Examples
Here is a simple snippet demonstrating this concept:
console.log(i);
}
const arr = [1, 2, 3];
for (const num of arr) { console.log(num); }\n```
### Explanation of Code
In the example above, we define the logic required to implement the concept, and then execute it. The JavaScript engine parses this syntax and runs it.
<Callout type="warning">
**Common Mistake:** Watch out for syntax errors! Missing a bracket or a semicolon can sometimes break your entire script.
</Callout>
### Try It Yourself
Put this into practice! The BrowserCode runtime allows you to execute JavaScript securely in your browser.
<TryItButton />
### Key Takeaways
- JavaScript makes pages interactive.
- Always check your browser console for errors.