What measures can affect the speed of Web page loading?

Absrtact: From I began to know SEO these years, basically all the SEO activities are based on the front-end, from the header to the body, from the label to the CSS, from the link to the keyword density; early cow people diagnose a website SEO standard is also from the front page, do not

From the beginning I know SEO these years, basically all of the SEO activities are based on the front-end, from the header to the body, from the label to the CSS, from the link to the keyword density; early cow people diagnose a website SEO standards also from the front page, but it is also, The code from the top of the ranking algorithm does account for most of the scale, but server speed optimization at the back end is becoming an increasingly important factor, especially as Google will use the site's speed as part of the algorithm.

Of course, the server that kind of thing should not be a seoer or semer should be proficient in the things, in fact, as long as the understanding and grasp the law on it (recommend another piece: Large-scale Web site architecture evolution and knowledge system), but still familiar with the Web site system or CMS acceleration means, as guoping in the How to form a very scientific system of SEO method Analysis of

What measures can affect the speed of Web page loading? network environment, server hardware, CMS itself can affect the speed of Web page loading. Optimizing any one of these can increase the speed of Web page loading. That immediately can be concluded: network environment Impact SEO traffic, server hardware impact SEO traffic, the speed of the CMS itself to affect the flow of SEO.

There are many factors affecting speed, here is a summary (excluding hardware)

This article refers to the 14 yahoo:best practices for speeding up Your Web Site and High-performance Web development

As much as possible to reduce the number of HTTP requests

This is the first one we know most seo, I do a simple description: Most of the HTTP request is front-end, the user most of the time is used to download pictures, CSS style sheets, various scripts, flash and so on. Of course, the Css,js file may be split into multiple because of CSS structure, shared and so on. Alibaba Chinese station at that time is the practice is still developed separately, and then in the background to the js,css to merge, so for the browser is still a request, but the development can still be restored to multiple, easy to manage and repeat references. Yahoo even recommends that the first page of CSS and JS directly written in the paging file, rather than external references. Because the number of visits to the home page is too large, this can also reduce two requests. In fact, many of the domestic portals are doing so.

The CSS sprites refers to using only the background image on the page to merge into one, and then through the CSS background-position attribute defined values to take his background. Taobao and Alibaba Chinese station are now doing so. Interested can look at Taobao and Alibaba background map.

http://www.csssprites.com/This is a tool site that automatically merges the images you upload and gives the corresponding background-position coordinates. The results are exported in PNG and GIF format.

Second, use CDN (content distribution Network) content IBuySpy Receptacle

Previously asked Zhang Zhiyong Childe about whether the CDN has an impact on the SEO, after consulting the technical manager's opinion, this effect can almost be ignored, but is the user side of the speed experience has been enhanced, the site's positive role is greater.

CDN acceleration is now very popular, almost a slightly larger site is useful for this service is to back up the site's mirror services to multiple server nodes, thereby speeding up the users around the server access.

More detailed content you can refer to Baidu Encyclopedia on the explanation of CDN

Third, add Expire/cache-control head

This rule has two things:

1. Static components: Set to Never expire, 2, to dynamic components: set to a reasonable cache control header to help conditional accordingly.

These files are cached by setting the Expires header. Expire is actually a header message to specify the cache time of a particular type of file in the browser. Most of the pictures, flash after the release is not necessary to modify, after the cache so that the browser will not need to download these files from the server but directly from the cache read, so that the speed of access to the page will be greatly accelerated.

A typical HTTP 1.1 protocol returns header information:

http/1.1 OK
Date:fri OCT 1998 13:19:41 GMT
server:apache/1.3.3 (Unix)
cache-control:max-age=3600, Must-revalidate
Expires:fri OCT 1998 14:19:41 GMT
Last-modified:mon June 1998 02:28:12 GMT
ETag: "3E86-410-3596FBBC"
content-length:1040
Content-type:text/html

Where Cache-control and expires can be completed by server-side scripting.

For example, set expires in PHP after 30 days:

<!–pheader ("Cache-control:must-revalidate"); $offset = * $ExpStr = "Expires:". Gmdate ("D, D M Y h:i:s", Time () + $offset). "GMT"; Header ($EXPSTR);–>

<!–pheader ("Cache-control:must-revalidate"); $offset = * $ExpStr = "Expires:". Gmdate ("D, D M Y h:i:s", Time () + $offset). "GMT"; Header ($EXPSTR);–>

Set absolute time expiration in asp:

<% response.expiresabsolute= #May 31,2010 13:30:15 gmt#%>

can also be done by configuring the server itself, these I am not very clear, hehe. Want to know more friends can refer to http://www.web-caching.com/

Iv. gzip Compression

This is currently the most application of the accelerated way, the code is very simple, gzip compression ratio is very large, the general compression rate of 85%, that is, server-side 100K of the page can be compressed to 25K and then sent to the client. Yahoo developers specifically stressed that all text content should be gzip compressed: HTML (PHP), JS, CSS, XML, txt.

Five, put the CSS on the top of the page

Put the script at the bottom of the page

Vii. avoid using expressions in CSS

CSS expressions are more often executed than we think, and tend to seriously affect performance. Moreover, it can only be performed in IE. So try to avoid it. This one has not thought before, personal use this is in the use of Max-width and min-width properties of IE. It is known that IE does not support max-width and Min-width attributes. Sometimes the page (especially the adaptive size of the page) in order to be able to small resolution to a certain extent can also show to use this function, how to do. My approach was to use expressions:

Viii. external JavaScript and CSS files

This earth man knows

IX. Reducing DNS queries

On the Internet, the domain name and IP address is one by one corresponding, domain name (semwatch.org) is very good to remember, but the computer does not know, the computer between the "Joseph" also to turn into IP address. Each computer on the network should have a separate IP address. The conversion work between domain name and IP address is called Domain name resolution, also known as DNS query. A DNS parsing process consumes 20-120 milliseconds, and the browser does not download anything under that domain until the DNS query is finished. Therefore, reducing the time of DNS query can speed up the loading of the page. Yahoo's proposal a page contains as many domain names as possible in 2-4. This requires a good plan for the overall page.

Ten, compressed JavaScript and CSS

Compressed JS and CSS around obviously, reduce the number of page bytes. Capacity small page load speed naturally also quickly. and compression in addition to reduce the volume can also play a certain degree of protection.

Of course, one of the drawbacks of compression is the readability of the code. I believe that a lot of friends who do front-end have encountered this problem: look at the effect of Google is cool, but to see his source code is a lot of crowded together characters, even function names are replaced, Khan die! Your own code is not so easy to maintain.

Xi. Yahoo developers tell us to avoid redirection

301,302 Redirect is the most common SEO, especially 301, the weight of the transfer and retention is very helpful, unless forced to, as little as possible with redirection.

12. Remove Duplicate Scripts

I do not want to say this also know, not only from the performance considerations, code specifications on the same. But admittedly, there are times when we add some code that might be repetitive.

13. Configure the Entity label (Configure ETags)

I do not understand this, hehe. On the Inforq found a more detailed explanation of the "use of etags to reduce Web application bandwidth and load," interested students can go to see.

14. Ajax caching (make Ajax cacheable)

Remember, even if Ajax is dynamically generated and works only for one user, they can still be cached

Evan Though your Ajax responses are created, and dynamically only is might to a single user, applicable can tightly be e.g.. Doing so'll make your Web 2.0 apps faster.

XV, Flush the Buffer Early

16. Use a for AJAX Requests

17, Post-load RS

18, preload RS

19. Reduce the number of DOM Elements

20, Split rs across Domains

21, Minimize the number of IFRAMEs

The frame is best not to use.

22, No 404s

This and SEO related terms are inconsistent, you can ignore ha.

23. Reduce Cookie Size

As far as possible, cookies are tracked, and may be more important than speed.

24, use Cookie-free Domains for RS

25. Minimize DOM Access

26, develop Smart Event handlers

27, Choose "link" over @import

28, Avoid Filters

29, Optimize Images

30, Optimize CSS Sprites

31, Don ' t Scale Images in HTML

32. Make Favicon.ico Sgt and cacheable

33, Keep RS under 25K

34. Pack Rs into a Multipart Document

35, Avoid Empty Image src

Avoid empty picture address links

Straight HTML

<img src= "" >

JavaScript

var img = new Image ();
IMG.SRC = "";

Both of these forms result in the same effect: The browser makes additional requests to the server

36, No.

Oh, too much.

Article Source: http://semwatch.org/2010/03/backend-seo-list-for-speed