NICOLE SULLIVAN Design Fast Websites
don’t blame the rounded corners!

Exceptional Performance
at Yahoo!

Quantify and improve the performance
of all Yahoo! products worldwide

Y! Performance Research Engineering Team
Nicole Sullivan, Anande Kishore (intern), Stoyan Stefanov, Philip Tellis, Swapnil Shinde

Make your users happy •
Users care if sites are fast. • I can’t give you the solution • I can help you understand the problem.

Why talk about
performance?

1: Because fast is better

2: Because sites are bigger

Modern web sites & applications
have changed architecturally.

From 2003 to 2008: 97K
to 312K. 25.7 to 49.9 objects.

In past 12 months, Top
1000 sites: From 250K to 310.4K. WebSiteOptimization.com/speed/tweak/average-web-page

3: Time is money

+100 ms

Amazon:1% drop in sales +100
ms

+400 ms

Yahoo!: 5-9% drop in full-page
traffic +400 ms

+500 ms

Google: 20% fewer searches +500
ms

Users care about
performance!

Performance Fruit (some low, some
high)

Web Dev Philosophy • Work
out of respect for the design. • Designers make our code as beautiful and clever on the outside as it is on the inside. • Respect the original design vision. consistent design = clean code = fast site.

9 Best Practices 1. Create
a component 5. Avoid non-standard library of smart objects browser fonts. 2. Use consistent semantic 6. Use columns rather than styles rows. 3. Design modules to be 7. Choose your bling transparent on the carefully. inside. 8. Be flexible. 4. Optimize images and sprites. 9. Learn to love grids.

1 Create a component library
of smart objects

Components are like legos Mix
and match to create diverse and interesting pages.

Site-wide legos: • Headings •
Lists (e.g. action list, external link list, product list, or feature list) • Module headers and footers • Grids • Buttons • Anything else that should be consistent site-wide.

Reusing elements makes them performance
“freebies”

Legos first Design individual pages
only once all the legos have been defined.

Avoid redundancy

Nearly identical modules Headings 3
and 5 are too similar.

Rule of thumb: If two
modules look too similar to include on the same page, they are too similar to include together in a site, choose one!

2
Use consistent
semantic styles

A Heading should not become
a Heading in another part of the page.

Consistent site-wide

Consistency Writing more rules to
overwrite the crazy rules from before. e.g. Heading should behave predictably in any module.

How about an example? Personal
finance

3 Design modules to be
transparent on the inside.

Contour blocks Background blocks Content
Objects - headings, paragraphs, lists, headers, footers, buttons, etc. Capital of the Canterbury region and the largest city on the South Island (population just over 300,000) exudes a palpable air of gentility and a connectedness with the mother country. Read more... X X 1:n

Making it look fab Requires
careful choice of pixels. Bonus: Consider PNG8 for progressive enhancement http://alistapart.com/articles/mountaintop/

Pitfalls
Variable or gradient
backgrounds.

4
Optimize images and
sprites

Optimize sprites 1. How many
pages does your property have? 2. Is your site modular? (hint: it should be!) 3. How much time can your team spend on site maintenance?

9 Image Optimizations 1. Combine
like colors 6. Reduce anti-aliased pixels - via size and alignment 2. Avoid whitespace 7. Avoid diagonal gradients 3. Horizontal better than vertical 8. Avoid alpha transparency 4. Limit colors 9. Change gradient color every 2-3 pixels 5. Optimize individual images, then sprite

Careful with Logos Very recognizable
so small changes will be noticed more easily.

Try progressively
enhanced PNG8

Avoid filters Why is the
AlphaImageLoader used? IE6 and earlier don’t natively support alpha transparency. This filter forces that support.

Problem with filters • Blocks
rendering, freezes the browser • Increased memory consumption • Per element, not per image!

Solution: Avoid AlphaImageLoader 1. BEST:
avoid completely, use PNG8 which degrades gracefully in IE < 7 2. Fallback: use underscore hack so the filter is applied only to IE < 7 #elem { background: url(some.png); _background: none; _filter:progid:DXImageTransform.Microsoft.AlphaImageLoader (src='some.png', sizingMethod='crop'); }

Progressively enhanced PNG8 Build a
binary transparency image. In Fireworks, add a few alpha transparent pixels.

IE6 Firefox Opera IE7+ Safari
Good browsers get more And the dinosaurs get an acceptable fallback

Experimental Data Removing Alpha Image
Loader 100ms Yahoo! search

Crush images Step 1: Quality,
Designer chooses quality (e.g. via save for the web) Step 2: Non-lossy compression to squeak the last bytes out of the image.

demo
http://smushit.com

5
Avoid non-standard
browser fonts.

6 Use columns rather than
rows.

7 Choose your bling carefully.
Consider your market and users.

8 Be flexible. Extensible height
and width.

• Grids control width •
Content controls height

9
Learn to love grids.

Flickr Photo Credits: • idigit_teddy:
http://www.flickr.com/photos/design_inspiration/238542495/ • lucianvenutian: http://www.flickr.com/photos/lucianvenutian/1142630637/ • Gimli_36: http://www.flickr.com/photos/navillot/1878124531/ • NathanFromDeVryEET: http://www.flickr.com/photos/ thatguyfromcchs08/2300190277/ • Stabilo Boss: http://flickr.com/photos/stabilo-boss/101793494/in/ set-72057594060779001/

Thanks! Nate Koechley - YUI.
High Performance Websites: ✴ http://www.slideshare.net/natekoechley/high-performance-web-sites-2008 Yahoo! Exceptional Performance Team: ✴ http://developer.yahoo.com/performance/ A list apart: ✴ http://alistapart.com/articles/mountaintop/ Tom Chi - Yahoo! Search

Let’s keep talking... http://developer.yahoo.com/performance/ http://stubbornella.org
nicole@stubbornella.org “stubbornella” on the web... twitter, dopplr, everywhere...