even faster web sites (inside ma.tt) best practices for faster pages
DESCRIPTION
Even Faster Web Sites (inside ma.tt) best practices for faster pages. Steve Souders [email protected] http://stevesouders.com/docs/wordcamp-20080816.ppt. Disclaimer: This content does not necessarily reflect the opinions of my employer. The Importance of Frontend Performance. 9%. 91%. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/1.jpg)
Steve [email protected]
http://stevesouders.com/docs/wordcamp-20080816.ppt
Even Faster Web Sites(inside ma.tt)
best practices for faster pages
Disclaimer: This content does not necessarily reflect the opinions of my employer.
![Page 2: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/2.jpg)
17%
83%
iGoogle, primed cache
The Importance of Frontend Performance
9% 91%
iGoogle, empty cache
![Page 3: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/3.jpg)
Time Spent on the Frontend
Empty Cache
Primed Cache
www.aol.com 97% 97%
www.ebay.com 95% 81%
www.facebook.com 95% 81%
www.google.com/search
47% 0%
search.live.com/results 67% 0%
www.msn.com 98% 94%
www.myspace.com 98% 98%
en.wikipedia.org/wiki 94% 91%
www.yahoo.com 97% 96%
www.youtube.com 98% 97%
![Page 4: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/4.jpg)
The Performance Golden Rule
80-90% of the end-user response time is spent on the frontend. Start there.
greater potential for improvement
simpler
proven to work
![Page 5: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/5.jpg)
14 Rules1. Make fewer HTTP
requests2. Use a CDN3. Add an Expires header4. Gzip components5. Put stylesheets at the
top6. Put scripts at the
bottom7. Avoid CSS expressions8. Make JS and CSS
external9. Reduce DNS lookups10.Minify JS11.Avoid redirects12.Remove duplicate
scripts13.Configure ETags14.Make AJAX cacheable
![Page 6: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/6.jpg)
High Performance Web Sites
YSlow
![Page 8: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/8.jpg)
High Performance Web Sites, Vol 2
1. Split the initial payload2. Load scripts without blocking3. Don't scatter inline scripts4. Split dominant domains5. Make static content cookie-free6. Reduce cookie weight7. Minify CSS8. Optimize images9. Use iframes sparingly10.To www or not to www
![Page 9: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/9.jpg)
AOLeBayFacebookMySpaceWikipediaYahoo!
Why focus on JavaScript?
YouTube
![Page 10: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/10.jpg)
Scripts Block
<script src="A.js"> blocks parallel downloads and rendering
What's "Cuzillion"?
http://stevesouders.com/cuzillion/?ex=10008
![Page 11: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/11.jpg)
JavaScript
Functions Executed before
onload
www.aol.com 115K 30%
www.ebay.com 183K 44%
www.facebook.com 1088K 9%
www.google.com/search
15K 45%
search.live.com/results
17K 24%
www.msn.com 131K 31%
www.myspace.com 297K 18%
en.wikipedia.org/wiki 114K 32%
www.yahoo.com 321K 13%
www.youtube.com 240K 18%
26% avg252K avg
Initial Payload and Execution
![Page 12: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/12.jpg)
Split the initial payload
split your JavaScript between what's needed to render the page and everything else
load "everything else" after the page is rendered
separate manually (Firebug); tools needed to automate this (Doloto from Microsoft)
load scripts without blocking – how?
![Page 13: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/13.jpg)
MSNScripts and other resources downloaded in parallel! How?var p= g.getElementsByTagName("HEAD")[0];var c=g.createElement("script");c.type="text/javascript";c.onreadystatechange=n;c.onerror=c.onload=k;c.src=e;p.appendChild(c)
MSN.com: Parallel Scripts
![Page 14: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/14.jpg)
Advanced Script Loading
XHR Eval
XHR Injection
Script in Iframe
Script DOM Element
Script Defer
document.write Script Tag
![Page 15: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/15.jpg)
XHR Eval
script must have same domain as main page
must refactor script
var xhrObj = getXHRObject();xhrObj.onreadystatechange = function() { if ( xhrObj.readyState != 4 ) return; eval(xhrObj.responseText); };xhrObj.open('GET', 'A.js', true);xhrObj.send('');
http://stevesouders.com/cuzillion/?ex=10009
![Page 16: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/16.jpg)
XHR Injectionvar xhrObj = getXHRObject();xhrObj.onreadystatechange = function() { if ( xhrObj.readyState != 4 ) return; var se=document.createElement('script'); document.getElementsByTagName('head') [0].appendChild(se); se.text = xhrObj.responseText; };xhrObj.open('GET', 'A.js', true);xhrObj.send('');
script must have same domain as main pagehttp://stevesouders.com/cuzillion/?ex=10015
![Page 17: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/17.jpg)
Script in Iframe<iframe src='A.html' width=0 height=0 frameborder=0 id=frame1></iframe>
iframe must have same domain as main page
must refactor script:// access iframe from main pagewindow.frames[0].createNewDiv();
// access main page from iframeparent.document.createElement('div');
http://stevesouders.com/cuzillion/?ex=10012
![Page 18: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/18.jpg)
Script DOM Elementvar se = document.createElement('script');se.src = 'http://anydomain.com/A.js';document.getElementsByTagName('head')[0].appendChild(se);
script and main page domains can differ
no need to refactor JavaScript
http://stevesouders.com/cuzillion/?ex=10010
![Page 19: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/19.jpg)
Script Defer<script defer src='A.js'></script>
only supported in IE
script and main page domains can differ
no need to refactor JavaScript
http://stevesouders.com/cuzillion/?ex=10013
![Page 20: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/20.jpg)
document.write Script Tagdocument.write("<scri" + "ipt type='text/javascript' src='A.js'>" + "</scri" + "ipt>");
parallelization only works in IE
parallel downloads for scripts, nothing else
all document.writes must be in same script block
http://stevesouders.com/cuzillion/?ex=10014
![Page 21: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/21.jpg)
Browser Busy Indicators
![Page 22: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/22.jpg)
Browser Busy Indicators
good to show busy indicators when the user needs feedback
bad when downloading in the background
![Page 23: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/23.jpg)
Ensure scripts execute in order:necessary when scripts have dependencies
IE: http://stevesouders.com/cuzillion/?ex=10017
FF: http://stevesouders.com/cuzillion/?ex=10018
Avoid scripts executing in order:faster – first script back is executed
immediatelyhttp://stevesouders.com/cuzillion/?ex=10019
Ensure/Avoid Ordered Execution
![Page 24: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/24.jpg)
Summary of Traits
*Only other document.write scripts are downloaded in parallel (in the same script block).
![Page 25: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/25.jpg)
and the winner is...
![Page 26: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/26.jpg)
Load Scripts without Blocking
don't let scripts block other downloads
you can still control execution order, busy indicators, and onload event
What about inline scripts?
![Page 27: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/27.jpg)
Inline Scripts after Stylesheets Block Downloading
Firefox blocks parallel downloads when downloading stylesheets
IE doesn't...
...unless the stylesheet is followed by an inline script
http://stevesouders.com/cuzillion/?ex=10021
best to move inline scripts above stylesheets or below other resources
use Link, not @import
![Page 28: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/28.jpg)
eBayMSNMySpaceWikipedia
Examples of Scattered Scripts
![Page 29: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/29.jpg)
Don't Scatter Inline Scripts
remember inline scripts carry a cost
avoid long-executing inline scripts
don't put inline scripts between stylesheets and other resources
![Page 30: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/30.jpg)
WordPress Analysis
![Page 31: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/31.jpg)
<head>
<style type="text/css" media="screen">
@import url( http://s.ma.tt/blog-content/themes/mahtete/style.css?6 );
@import url( http://s.ma.tt/blog-content/themes/mahtete/double-col.css?4 );
</style>
[snip...]
<script type='text/javascript' src='http://s.ma.tt/blog/wp-includes/js/jquery/jquery.js?ver=1.2.6'></script>
<script type='text/javascript' src='http://s.ma.tt/photos/suggest.js'></script>
<link rel="stylesheet" href="http://s.ma.tt/photos/suggest.css" />
<script type="text/javascript">
var $j = jQuery.noConflict();
[snip...]
</script>
</head>
IE
FF
@import parallelizes stylesheets in FFavoids script blocking in IE
ma.tt Head Analysis
![Page 32: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/32.jpg)
<head>
<style type="text/css" media="screen">
@import url( http://s.ma.tt/blog-content/themes/mahtete/style.css?6 );
@import url( http://s.ma.tt/blog-content/themes/mahtete/double-col.css?4 );
</style>
[snip...]
<script type='text/javascript' src='http://s.ma.tt/blog/wp-includes/js/jquery/jquery.js?ver=1.2.6'></script>
<script type='text/javascript' src='http://s.ma.tt/photos/suggest.js'></script>
<link rel="stylesheet" href="http://s.ma.tt/photos/suggest.css" />
<script type="text/javascript">
var $j = jQuery.noConflict();
[snip...]
</script>
</head>
IE
FF
scripts block parallel downloads (except @import in IE)
ma.tt Head Analysis
![Page 33: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/33.jpg)
<head>
<style type="text/css" media="screen">
@import url( http://s.ma.tt/blog-content/themes/mahtete/style.css?6 );
@import url( http://s.ma.tt/blog-content/themes/mahtete/double-col.css?4 );
</style>
[snip...]
<script type='text/javascript' src='http://s.ma.tt/blog/wp-includes/js/jquery/jquery.js?ver=1.2.6'></script>
<script type='text/javascript' src='http://s.ma.tt/photos/suggest.js'></script>
<link rel="stylesheet" href="http://s.ma.tt/photos/suggest.css" />
<script type="text/javascript">
var $j = jQuery.noConflict();
[snip...]
</script>
</head>
IE
FF
put stylesheets before scripts
ma.tt Head Analysis
![Page 34: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/34.jpg)
<head>
<style type="text/css" media="screen">
@import url( http://s.ma.tt/blog-content/themes/mahtete/style.css?6 );
@import url( http://s.ma.tt/blog-content/themes/mahtete/double-col.css?4 );
</style>
[snip...]
<script type='text/javascript' src='http://s.ma.tt/blog/wp-includes/js/jquery/jquery.js?ver=1.2.6'></script>
<script type='text/javascript' src='http://s.ma.tt/photos/suggest.js'></script>
<link rel="stylesheet" href="http://s.ma.tt/photos/suggest.css" />
<script type="text/javascript">
var $j = jQuery.noConflict();
[snip...]
</script>
</head>
IE
FF
ma.tt Head Analysis
don't put inline scripts between stylesheets and other resources
![Page 35: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/35.jpg)
Analyzing All of ma.tt
good:• 10 images sprited into 1• CDN: s.ma.tt (Panther), stats.wordpress.com (Savvis)• expires set 2-5 days in the future• most everything gzipped• most .js minified• ETags configured• parallelized stylesheets
fix:• combine scripts (4), combine stylesheets (3)• sprite CSS background images (15)• move scripts to bottom, load non-blocking• shard resources across 2-4 domains• cookieless domain for static content (7K across 30 requests)• move inline script after stylesheet• stylesheet above .js• image height & width
![Page 36: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/36.jpg)
Analyzing All of ma.tt
![Page 37: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/37.jpg)
Analyzing All of ma.tt
26% 12%
![Page 38: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/38.jpg)
Announcement 1: HTTPWatch for FF
http://httpwatch.com/
previously IE only
Firefox private beta now
Firebug 1.05 Net Panel buggy
![Page 39: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/39.jpg)
Announcement 2: Firebug Lite 1.2
http://getfirebug.com/lite.html
console.log
Inspect
DOM and CSS
![Page 40: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/40.jpg)
Announcement 3: Mozilla & Firebug
John Resig, Rob Campbell, Jan Odvarko
Firebug Working Group
stability, performance, bug fixes
![Page 41: Even Faster Web Sites (inside ma.tt) best practices for faster pages](https://reader035.vdocument.in/reader035/viewer/2022070405/56814029550346895dab8a9e/html5/thumbnails/41.jpg)
Takeaways
focus on the frontend
run YSlow: http://developer.yahoo.com/yslow
this year's focus: JavaScriptSplit the Initial PayloadLoad Scripts without BlockingDon't Scatter Inline Scripts
speed matters
life's too short, write fast codeblogs