Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Lazy Load Everything!
Search
Sebastiano Armeli
October 18, 2012
Programming
3
410
Lazy Load Everything!
Talk given at Web Directions South, Sydney - October 2012
Sebastiano Armeli
October 18, 2012
Tweet
Share
More Decks by Sebastiano Armeli
See All by Sebastiano Armeli
Cultivate Excellence In Engineering Teams through Continuous Software Engineering
sebarmeli
1
150
From Strategy Definition to Execution with OKRs and Roadmap
sebarmeli
0
150
From Mission to Strategy: going over OKRs and Roadmap
sebarmeli
0
270
Managing a software engineering team
sebarmeli
1
590
Enforcing coding standards in a JS project
sebarmeli
0
580
Enforcing Coding Standards
sebarmeli
1
120
ES6: The future is now
sebarmeli
2
480
EcmaScript 6 - the future is here
sebarmeli
5
7.2k
Dependency management and Package management in JavaScript
sebarmeli
0
730
Other Decks in Programming
See All in Programming
A2A プロトコルを試してみる
azukiazusa1
2
1.4k
新メンバーも今日から大活躍!SREが支えるスケールし続ける組織のオンボーディング
honmarkhunt
5
7.2k
Blazing Fast UI Development with Compose Hot Reload (droidcon New York 2025)
zsmb
1
290
PHPで始める振る舞い駆動開発(Behaviour-Driven Development)
ohmori_yusuke
2
390
PicoRuby on Rails
makicamel
2
130
「Cursor/Devin全社導入の理想と現実」のその後
saitoryc
0
820
技術同人誌をMCP Serverにしてみた
74th
1
640
20250704_教育事業におけるアジャイルなデータ基盤構築
hanon52_
5
780
High-Level Programming Languages in AI Era -Human Thought and Mind-
hayat01sh1da
PRO
0
770
第9回 情シス転職ミートアップ 株式会社IVRy(アイブリー)の紹介
ivry_presentationmaterials
1
320
Claude Code + Container Use と Cursor で作る ローカル並列開発環境のススメ / ccc local dev
kaelaela
9
5.1k
Hypervel - A Coroutine Framework for Laravel Artisans
albertcht
1
120
Featured
See All Featured
GraphQLとの向き合い方2022年版
quramy
49
14k
The Power of CSS Pseudo Elements
geoffreycrofte
77
5.9k
JavaScript: Past, Present, and Future - NDC Porto 2020
reverentgeek
50
5.5k
Scaling GitHub
holman
460
140k
Being A Developer After 40
akosma
90
590k
Making Projects Easy
brettharned
116
6.3k
Bootstrapping a Software Product
garrettdimon
PRO
307
110k
RailsConf & Balkan Ruby 2019: The Past, Present, and Future of Rails at GitHub
eileencodes
138
34k
Statistics for Hackers
jakevdp
799
220k
Visualization
eitanlees
146
16k
[RailsConf 2023] Rails as a piece of cake
palkan
55
5.7k
Designing for Performance
lara
610
69k
Transcript
LAZY LOAD EVERYTHING! Sebastiano Armeli @sebarmeli Web Directions South 2012,
Sydney Monday, 3 June 13
LAZYNESS?? Monday, 3 June 13
PERFORMANCE Monday, 3 June 13
• Asynchronous calls • Load on-demand LAZY LOADING • window
‘onload’ NOT delayed • Driven by Events Monday, 3 June 13
What can we lazy load? Monday, 3 June 13
<script> </script> Monday, 3 June 13
<body> <!-- Page content --> <img .../> <!--JS concatenated, at
the bottom--> <script src=”js/one.min.js”></script> </body> Concatenation Monday, 3 June 13
‘onload’ ‘DOMContentLoaded’ Monday, 3 June 13
DRAWBACKS • No parallel downloads • Limit bene!ts from caching
• Limit bene!ts from CDN • ‘DOMContentLoaded’ still late Monday, 3 June 13
var g = document.createElement('script'); g.type = 'text/javascript'; g.async = true;
g.src = 'js/third_party.js'; var s = document. getElementsByTagName('script')[0]; s.parentNode.insertBefore(g, s); Dynamic <script> Monday, 3 June 13
<script async src="script.js"></script> HTML 5 Async Monday, 3 June 13
$(window).load(function(){ // Async insert <script> var g = document.createElement('script'); g.type
= 'text/javascript'; g.async = true; g.src = 'js/third_party.js'; var s = document. getElementsByTagName('script')[0]; s.parentNode.insertBefore(g, s); }); Async + Event-driven Monday, 3 June 13
after ‘onload’ Monday, 3 June 13
What if some JS code depends on a lazy-loaded file?
Monday, 3 June 13
Monitor readyState attribute Monday, 3 June 13
• Dependecy Management • Intuitive methods to load JS SCRIPT
LOADERS • Parallel downloads Monday, 3 June 13
$('img').click(function(){ yepnope.injectJs("script.js", function(){ // Executed when the script is loaded
console.log("Hi!"); }); }); YepNope.js Monday, 3 June 13
Lazy load assets based on visibility Monday, 3 June 13
function loadVisible(el, script, callback) { var rect = el.getBoundingClientRect(); if
(rect.top >= 0 && rect.left >= 0 && rect.bottom <= window.innerHeight && rect.right <= window.innerWidth) { // Load the script yepnope.injectJs(script, function(){ if (callback) { callback(); } }); } } Monday, 3 June 13
<img> Monday, 3 June 13
The problem Visible and not visible images are loaded Monday,
3 June 13
JAIL LazyLoad YUI ImageLoader or ... mod_pagespeed Monday, 3 June
13
JAIL.js • jQuery plugin by @sebarmeli • Easy to use
-> $(‘img’).jail() • ‘data-src’ attribute • A few con!gurations available Monday, 3 June 13
// Images loaded scrolling down $(function(){ $(‘img’).jail(); }); // Images
loaded after an event $(function(){ $(‘img’).jail({ triggerElement: ‘a.link’, event: ‘click’ }); }); Monday, 3 June 13
4 images downloaded after ‘onload’ in different moments! Monday, 3
June 13
Monday, 3 June 13
Monday, 3 June 13
http://requirejs.com http://yepnopejs.com/ http://sebarmeli.github.com/jail @sebarmeli https://gist.github.com/3899364 Monday, 3 June 13