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
140
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
なんとなくわかった気になるブロックテーマ入門/contents.nagoya 2025 6.28
chiilog
1
190
イベントストーミング図からコードへの変換手順 / Procedure for Converting Event Storming Diagrams to Code
nrslib
1
320
Railsアプリケーションと パフォーマンスチューニング ー 秒間5万リクエストの モバイルオーダーシステムを支える事例 ー Rubyセミナー 大阪
falcon8823
4
920
datadog dash 2025 LLM observability for reliability and stability
ivry_presentationmaterials
0
110
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
230
都市をデータで見るってこういうこと PLATEAU属性情報入門
nokonoko1203
1
560
PostgreSQLのRow Level SecurityをPHPのORMで扱う Eloquent vs Doctrine #phpcon #track2
77web
2
290
ruby.wasmで多人数リアルタイム通信ゲームを作ろう
lnit
2
250
たった 1 枚の PHP ファイルで実装する MCP サーバ / MCP Server with Vanilla PHP
okashoi
1
170
Bytecode Manipulation 으로 생산성 높이기
bigstark
2
370
来たるべき 8.0 に備えて React 19 新機能と React Router 固有機能の取捨選択とすり合わせを考える
oukayuka
2
840
Webの外へ飛び出せ NativePHPが切り拓くPHPの未来
takuyakatsusa
2
340
Featured
See All Featured
How to Think Like a Performance Engineer
csswizardry
24
1.7k
Chrome DevTools: State of the Union 2024 - Debugging React & Beyond
addyosmani
7
700
Building Flexible Design Systems
yeseniaperezcruz
328
39k
Code Review Best Practice
trishagee
68
18k
The Psychology of Web Performance [Beyond Tellerrand 2023]
tammyeverts
48
2.8k
Rails Girls Zürich Keynote
gr2m
94
14k
The Pragmatic Product Professional
lauravandoore
35
6.7k
Raft: Consensus for Rubyists
vanstee
140
7k
Code Reviewing Like a Champion
maltzj
524
40k
The Art of Delivering Value - GDevCon NA Keynote
reverentgeek
15
1.5k
No one is an island. Learnings from fostering a developers community.
thoeni
21
3.3k
CoffeeScript is Beautiful & I Never Want to Write Plain JavaScript Again
sstephenson
161
15k
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