Detailed explanation of examples of html page optimization

1. Reduce the number of HTTP requests.

(1) Merge JS files and CSS files.

(2) Merge frame images and relatively less changed images into one, and complete rendering through CSS background cutting.

(3) Reasonably use local Cache to cache JS/CSS/IMAGE.

2. Reduce the size of the requested file and reduce the network bandwidth occupied by the requested data.

(1) Compress JS volume: delete blank line breaks, comments, and obfuscation in JS, and replace long variables with short variables.

(2) Compress CSS volume: delete CSS comments and use abbreviations as much as possible.

(3) Use (X)HTML+CSS to build the website structure and provide CSS reusability to reduce the size of (X)HTML files.

(4) Use server-side GZIP to compress JS/CSS files to reduce the size of the transferred files.

3. Control client cache through versioning.

How to update these cached files in time? Through a simple configuration, you can tell the browser in time by modifying the JS version that these files must be requested again and do not continue to use the data in the browser cache. There are several solutions:

(1) Manually change the file names of these JS.

(2) Manually change the paths of these JS.

(3) Relocate the JS path through URL Rewrite.

(4) Inform the page through a JS configuration on a high-response server which JS files should be linked to this page.

(5) The large version remains unchanged, the small version is continuously added, and will be updated uniformly after a certain period of time to efficiently utilize the cache.

4. Help the page lose weight.

5. Delete some dispensable content on the page.

Mainly refers to redundant spaces, tabs, blank lines, double quotes, single quotes, comments, etc.

6. Delete empty statements in the web page code.

For example:

<span style=&#39;font-family:宋体&#39;>你好<span lang=EN-US><o:p></o:p></span></span>

Obviously, the sentences after "Hello" have no effect, we can delete them.

7. Delete the default attributes of HTML.

HTML language has many default attributes, such as alignment, fonts, colors, etc., but web page production software will add these useless codes. For example: the align attribute defaults to left alignment, so we don’t need to write "align=left" when aligning to the left.

8. Optimize CSS.

For example: use abbreviated CSS.

Or:

<p class="decorated">1</p>
    <p class="decorated">2</p>
    <p class="decorated">3</p>
    <p class="decorated">4</p>

You can use p to include:

  <p class="decorated">
        <p>1</p>
        <p>2</p>
        <p>3</p>
        <p>4</p>
    </p>

9. Visibility is faster than Display.

10. Keep the case consistent for the same URL.

Internet Explorer’s buffer also treats uppercase and lowercase strings differently. Therefore, as a web developer, you must remember to keep the capitalization of URL strings for the same link consistent in different locations. Otherwise, different file backups of the same location will be stored in the browser's buffer, which will also increase the number of requests to download content from the same location.

11. Let the mark have a beginning and an end.

12. Do not stuff the entire page content into a Table.

Because the Table will be displayed after all the contents are added, if some contents are inaccessible, it will delay the access speed of the entire page. The correct approach is to divide the content into several Tables with the same format, rather than cramming them all into one Table.

13. Use iframe to nest another page.

If you need to insert advertising code and don’t want to affect the speed, then using iframe is the most suitable. The display of the page will not be affected by the delay of the advertising code.

14. Move JavaScript to the end of the HTMl file.

Because JavaScript will block the display of subsequent pages during processing, and will also block HTML requests.

15. The knowledge of friendly links.

(1) Only make text links. Making text links will not delay the speed of the web page.

(2) Put all links into a separate paging area, and then link to the page on the home page.

(3) If the friendly link must appear on the homepage, then please put the entire Table where the link is located at the bottom of the page, because the page is displayed line by line from top to bottom.

(4) Download the logo image of the friendly link first and then upload it to your own web space.

16. Image optimization.

(1) Reduce the number of pictures: remove unnecessary pictures.

(2) Reduce image quality: For pictures in JPG format, pictures that are reduced by 5% do not seem to have changed much, but the file size changes significantly.

(3) Use the appropriate format: JPG is generally used to display photography works of landscapes, people, and artistic photos, and is sometimes used in computer screenshots; GIF provides fewer colors and can be used in some applications that require color. Low-profile places, such as website logos, buttons, emoticons, etc.; PNG format can provide a transparent background and is generally used on web pages that require transparent background display or have higher image quality requirements.

17. Add a slash after the URL.

When the server receives such an address, it takes time to determine the file type of this address. If 220 is a directory, you might as well add an extra slash after the URL, so that the server will know at a glance that it wants to access the index or default file in the directory, thus saving time.

18. Indicate height and width.

If there is no setting, the browser will calculate the size while downloading the image. If there are many images, the browser will need to constantly adjust the page, which not only affects the speed, but also affects the browsing experience. When the browser knows the height and width, even if the image cannot be displayed, it will make room for the image on the page and continue to load the following content. As a result, it loads faster and the browsing experience is better.

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