Improve Web Page Performance
 

Competition is increasing on the Web. If your site is slow you will lose to your competitors. To improve web page performance (speed), you can do a number of things:

1. increase number of servers
2. tweak your server(s)
3. modify your web pages

This article will focus on modifying your web pages to increase performance.

As you are aware, today's browsers are faster than earlier versions. They have changed functionality to help improve speed. By understanding how browsers function, you will be able to increase your web page performance.

Learn everything that you can about browser functionality....
http://www.browserscope.org/ is a great resource that charts how different browsers function.

The Easiest Thing You Can Do To Improve Web Page Performance:

1. Use less <tables> - if a product requires you to wrap large chunks of code within a <table> you should think twice about it
2. Remove unnecessary objects, features, and plugins.
3. Reuse static files across multiple domains. eg. images, css, js, etc
4. Use less javascript - if a product requires additional javascript you should think twice about it; javascript blocks everything from loading (in parallel) until completely loaded and processed

Javascript blocks other files from downloading - It also needs time from processing. So, the less you have the faster your speed.

http://content.screencast.com/users/...9-17.58.22.png

Read more about how <tables> affect speed...
How Design Affects Performance : Progressive Rendering

Additional information...
How Design Affects Performance

Increase Download Parallelization - Use A CDN Such As Amazon S3:

Increase download parallelization by increasing the number of resources that serves static files. In other words, if you have many static objects* on a page split them across multiple domains.

*static files - includes stylesheets, images, swf, etc

The reason why this works is because each browser allows a maximum number of connections per hostname. In modern browsers, this number has increased to 6 (avg). What this means is that your browser will try to download 6 objects from any hostname at the same time. So if you increase the number of resources that serve static files it's more likely that you will decrease page display time.

In comparison, older browsers such as IE 6 only allowed 2 maximum connections per hostname.

Move all your static files to a CDN such as Amazon S3. Doing so will provide you with the following:

1. decrease server load
2. decrease bandwidth
3. decrease cost
4. decrease page display time

Get yourself an S3 account ASAP!

I recommend using a different domain other than your site domain. The reason behind this is that you don't want your cookies associated with each static file.

1. There's no need to associate cookies with static files.
2. Some cookies can be as long as 1k which will increase your time.

the following image is a snapshot of the headers of a downloaded image...

http://content.screencast.com/users/...9-17.19.49.png

Getting Started

I elect to use .info domain for static files as they are offered on the cheap - $1.99.

For example, if your site domain is domain.com ; you should purchase domain-file.info to serve your static files.

(Note: It can be any domain just as long as it's different from your site.)

Setting Up Your Domain

Once you get your domain you can point it to your amazon s3 server account (url). This is done by adding a CNAME entry for each sub-domain that you want to create.

I created the following sub-domains:

• js.domain-file.info to serve javascript files
• css.domain-file.info to serve stylesheets
• img.domain-file.info to serve images
• img2.domain-file.info to serve images
• icons.domain-file.info to serve icons if you have a large amount of icons

To upload files, I highly recommend using a commercial product called Bucket Explorer. There is a free Firefox extension, S3Fox Organizer, that provides a GUI interface but it lacks a lot of features.

Whatever you use - make sure that you can alter headers.

You will need to add EXPIRES header so that the static files are cached - saving you bandwidth and decreasing overall page display time.

Other Things You Can Do To Speed Up Your Pages (in no particular order):

• combine javascript (to decrease http request)
• move javascript to the <head> or to the footer (below any content)
• decrease number of inline javascript
• combine css (to decrease http request)
• combine images using sprites (to decrease http request)
• load css prior to any javascript calls
• compress images

Compress Javascript & Stylesheets:

To further decrease page display time, I recommend compressing (gzip) your js and css files. You will then have to create a plugin to show the gzip version if browser is capable of displaying if not show the uncompressed version.

Most modern browsers are capable of displaying compressed files. However, IE6 is known to have some issues - yes, even the SP2 which was reported to have this fixed is still buggy.

Tools To Help You Get Started

• Firebug
• YSlow
• Page Speed by Google

Thanks a lot for this very useful article.
Just signed up for S3 account and start doing some of the things you recommend.

1) I have some parked domains which i can use to host files. Say, I have the .info parked on top of my .com.
It seems like I have to create an account for that .info and create subdomains on .info in order to add CNAME?

2) How do I add EXPIRES in the images from Bucket Explorer. When I tried to do that, it always result in https, instead of http.

3) Do you recommend moving all Vbulletin styles images folder off to S3?

once you have your S3 account setup just create new buckets with the same name as your subdomains

for example...
if you create the following sub-domain:
- css.domain.info
- images.domain.info
- etc

your buckets will be called:
- css.domain.info
- img.domain.info
- etc


if creating the following CNAMEs...
- css.domain.info
- img.domain.info
- etc

you should point them to...
- css = css.domain.info.s3.amazonaws.com
- img= img.domain.info.s3.amazonaws.com
- etc

yes

Thanks Princeton,

Got the S3 working and the subdomain properly redirects. I'm moving some images now.
Now, I believe the Expires is set in the apache server, not for individually images, correct?

use the Bucket Explorer Batch Operation / Metadata to set Expires

Key = Expires
value = sometime in the future ex. Thu, 01 Dec 2010 11:16:04 GMT

Thanks Princeton this is exactly what Ive been looking for.

Question, Can I move all the VB js scripts into a single file? Im assuming VB wrote it this way for a reason.

Also can I move all my extra Css into the default VB css? I have 5 customs styles on the site and I wasn't sure if that would overlap them.

Thanks again... Daniel

No, it's impossible with the current setup
if you merge them into 1 file you will get errors

(you need to worry about execution order, etc)

this is possible - I'm assuming you want to create 5 separate css stylesheets.

As for the JS that's what I thought. I can combine them as long as they have nothing to do with page placement. Correct?


And for the CSS Ive combined all the extra into one file and placed it at the top of the head. Is it really much of a time saver to add them into each stylesheet?

I recommend running tests to find out what files you can merge.

confused ... are you suggesting to merge all stylesheets into 1 file? If so, it's not needed nor recommended.

the idea here is to decrease bandwidth but also to generate the pages faster