Track
javascript
JavaScript
36 lessons: values, DOM, events, async/await, modules—browser playground and 108 MCQs. Prerequisite for TypeScript and frameworks.
- Mode
- client_javascript
- Practice
- In-browser JS
- Lessons
- 36 units
Before you start
The programming language of the browser: values, functions, DOM APIs, events, and async patterns.
Interactivity, validation, and client-side data handling all depend on JavaScript.
Browsers, Node.js services, edge workers, and tooling ecosystems (bundlers, test runners).
In-browser playground on every lesson, hands-on challenges, interview prep, and three MCQs per slug.
After HTML/CSS fundamentals—before TypeScript and any front-end framework track.
Lesson order
Sequential — follow top to bottom36 lessons are live in this track. Start from step 01 for the smoothest path.
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01 intro Introduction to JavaScript
beginner
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02 what-is-javascript What is JavaScript?
beginner
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03 how-js-runs How JavaScript runs in the browser
beginner
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04 playground-workflow Playground workflow
beginner
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05 devtools-console DevTools and the console
beginner
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06 variables-let-const let, const, and var
beginner
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07 data-types-primitives Primitives and typeof
beginner
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08 operators-comparisons Operators and comparisons
beginner
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09 strings-template-literals Strings and template literals
beginner
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10 arrays-basics Arrays basics
beginner
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11 objects-basics Objects basics
beginner
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12 conditionals-if-else Conditionals
beginner
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13 switch-ternary switch and ternary
beginner
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14 loops-for-while Loops
beginner
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15 functions-declarations Function declarations
beginner
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16 arrow-functions Arrow functions
intermediate
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17 scope-closures-intro Scope and closures intro
intermediate
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18 dom-selection DOM selection
intermediate
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19 dom-manipulation DOM manipulation
intermediate
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20 events-listeners Events and listeners
intermediate
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21 event-delegation Event delegation
intermediate
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22 forms-validation-preview Forms and validation preview
intermediate
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23 fetch-json-preview fetch and JSON preview
intermediate
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24 promises-basics Promises basics
intermediate
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25 async-await async/await
intermediate
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26 error-handling-try-catch Error handling
intermediate
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27 modules-esm-preview ES modules preview
intermediate
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28 json-localstorage JSON and localStorage
intermediate
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29 timers-debounce-preview Timers and debounce preview
intermediate
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30 destructuring-spread Destructuring and spread
intermediate
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31 map-filter-reduce map, filter, reduce
intermediate
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32 classes-es6-intro Classes intro
intermediate
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33 debugging-techniques Debugging techniques
advanced
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34 typescript-bridge-lesson TypeScript bridge
intermediate
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35 interview-essentials-javascript Interview essentials
advanced
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36 production-js-checklist Production JavaScript checklist
advanced
Open →