JavaScript in Depth
JS: Filename Extension
By Xah Lee. Date:
2025-05-21
. Last updated:
2025-11-18
.
.js
normal JavaScript filename extension
.mjs
sometimes used for JavaScript modules.
JS: Module
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HTML
CSS
JS
JS Obj Ref
DOM
SVG
JS
Basics
Filename Extension
Run JavaScript
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Quote String
Number
Math Operators
Assignment
Boolean
Test Equality
Conditional
Loop
Array Tutorial
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Value Types
Value Types
Variable
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String
String Overview
Regular Expression
Property
Property Overview
Object and Inheritance
Object Overview
Array
Array Overview
Function
Function Overview
Class
Class Overview
Iterable
Iterable
for-of Loop
Spread Operator
Misc
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Map
Import
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Promise
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Try Catch Throw
Style Guide
Semicolon
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Timing JS Code
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