Lessons
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Introduction
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Search engine optimization
- Broken links
- Site map
- Micro-markup
- Robots.txt
- References
- Text
- Duplicates
- Basic
- Pictures
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Speed
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Minification
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Minification of CSS to reduce its volume
Minification of JavaScript files
Minification of inline CSS code
Minification of images without loss of quality
Minification of JavaScript files to reduce its volume
Unused CSS code
Data optimization:Image URLs
Animated image format MP4 and WEBM instead of GIF and WEBP
Unused JavaScript code
Using the WebP format in images
Too high-quality images without using compression
Suitable video bitrate
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Reducing requests
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An overabundance of small pictures
Grouping CSS files
Grouping JavaScript files
An overabundance of font files
Availability of end-to-end CSS, JS files
The presence of a monochrome font
Uploading duplicate files
Using JavaScript facades
Redirecting JavaScript code
Adding lazy loading
Redirect from/to www version
- Fonts
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Loading time
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Acceptable size of the HTML code of the page
HTML code generation time
The total volume of all images on the page
Total loading time
Total page load time.
Display time of the first graphic
Optimal time to download files from the server
Time to download files from the server under load
Blocking files
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Server Settings
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304 response code when checking the operation of caching
ETag header for caching operation
The "Expires" header for caching to work
Server GZip compression function
Title "Keep alive"
Redirects when uploading files
Using the modern HTTP2 protocol to speed up the site
- Pictures
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The first content
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The sequence of connecting JavaScript files
Font display mode
Setting up a pre-connection
Removing lazy loading
Long JavaScript code execution time
File upload delayed or on demand
The server is located in the same country where the users of the site live
Requests to another country that cause page loading to be blocked
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Minification
- Mobility
- Bugs
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Convenience
- Social networks
- Web Application Manifest
- Favicons
- Basic
- Text readability
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Security
- Encrypted connection
- Exploits
- Vulnerabilities
304 response code when checking the operation of caching
The page consists of dozens of files, and 95% of the files can be shared by all pages of the site. Caching was invented to avoid downloading this information every time.
There are 3 caching mechanisms:
- The “cache-control” or “expires” headers indicate how long the content will be relevant. During this time, the user’s browser uses the saved copy of the file and does not make any requests to the server.
- Caching via “etag”. The server generates a unique string based on the content and the user’s browser asks each time if the file has changed and provides this string.
- The title is “Last-Modified”. The server reports the date of the last file change, and the browser asks each time if the file has changed since that time.
When the browser makes a request to the server about whether the file has changed, the server should respond with a 304 code. If this does not happen, then caching does not work. This slows down the loading of the site’s pages.
Instruction [How to set up caching] (/blog/apache_i_nginx_tyuning_bystrodeystviya).
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