Ire Aderinokun • 2/28/2017

Asynchronous vs Deferred JavaScript

Read Original

This technical article compares asynchronous and deferred JavaScript execution, explaining how these script attributes affect the browser's critical rendering path. It details the default blocking behavior, how `async` allows parallel download with immediate execution, and how `defer` delays execution until after HTML parsing, providing guidance on when to use each method for optimal page performance.

0 comments
#JavaScript #performance #async
Asynchronous vs Deferred JavaScript

Comments

No comments yet

Be the first to share your thoughts!

Browser Extension

Get instant access to AllDevBlogs from your browser

Top of the Week

1
React vs Browser APIs (Mental Model)
Jivbcoop • 4 votes
2
React, useEffect, and Stale Closures: How to Avoid Them with Dependencies and useRef
Jivbcoop • 3 votes
3
Better react-hook-form Smart Form Components
Maarten Hus • 2 votes
4
Building Type-Safe Compound Components
TkDodo Dominik Dorfmeister • 2 votes
5
Dew Drop – January 15, 2026 (#4583)
Alvin Ashcraft • 1 votes
6
Using Browser Apis In React Practical Guide
Jivbcoop • 1 votes
7
Building a Complete FIRE Calculator App with GitHub Copilot in One Chat Session
James Montemagno • 1 votes