enhance performance or optimal performance

How to optimize performance of web？

There are seven aspects of enhancing web pages loading performance

1. webpage content

• decrease the number of the http request
• decrease the number of the DNS-search
• avoid redirection problem
• avoid 404 error
• cache ajax request
• delay loading
• load beforehand
• decrease the number of DOM in the webpage content
• use different domain to load content
• decrease using the frame possibly

2. server

• use the CDN
• add the expires or cache-control into reponse-header
• use GZIP
• use Etag (this way can avoid 304)
• export cache quickly and early
• avoid the image's src is null
• use the get method of the ajax

3. cookie

• compress the size of cookie
• use domain with no-cookie of static resource

4. css

• the css should stay at the head tag
• don't use the expression of css
• use Link better than @important
• don't use filter?

5. javascript

• the js file should stay at the body's ending
• compress the size of js file
• decrease the operation of the DOM
• don't use the repeated js file
• use more effective event

6. picture

• use sprite
• optimize picture
• use favicon.ico
• don't scale picture in the structure of html

7. mobile app

• keep every file's size is less than 25kb
• pack the webpage into multipart
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