Lessons
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Introduction
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SEO
- Snippet CTR
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Indexing
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Headings H1-H6
Images have the alt attribute.
The Title attribute of links
Splitting the page into HTML5 sections
Content robots.txt
Duplicate "title"
Duplicate "description"
Human-understandable name of the picture
Rules for formatting text on a page
Micro-markup format requirements and recommendations
Validation microdata Google
Human-friendly link format
Errors in Robots.txt
The content of the site map
The site map file
Link formatting requirements
Hreflang tag
"canonical" tag
Spelling of interactive interface elements
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Speed
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Number of network requests
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An overabundance of small pictures
Grouping CSS files
Grouping JavaScript files
An overabundance of font files
Redirects when uploading files
Availability of end-to-end CSS, JS files
Uploading duplicate files
Using JavaScript facades
Redirecting JavaScript code
Redirect from/to www version
Using sprite technology
The video player is connected correctly
- General assessment
- Caching
- Showing the first content
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File size
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Minification of CSS to reduce its volume
Server GZip compression function
Minification of the embedded JavaScript code of the page
Acceptable size of the HTML code of the page
Minification of the embedded CSS code of the page
Minification of images without loss of quality
Minification of JavaScript files to reduce its volume
The total size of all images on the page
Unused CSS code
Font Optimization
An overabundance of monochrome icons
The presence of a monochrome font
Data optimization:Image URLs
Animated image format MP4, WEBM, SVG instead of GIF and WEBP
Unused JavaScript code
Cropping monophonic fields in images
Using the WebP format in images
Too high-quality images without using compression
Suitable video bitrate
Excessively large images
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Slow files
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HTML code generation time
Title "Keep alive"
Optimal time to download files from the server
Using the modern HTTP2 protocol to speed up the site
Adding lazy loading
Long JavaScript code execution time
Time to download files from the server under load
The server is located in the same country where the users of the site live
No requests to another country that cause page loading to be blocked
Blocking files
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Number of network requests
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Mobile adaptation
- Broken layout
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Compliance with guidelines
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Finger friendly
Blurry images
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Software errors
- Code
- Mail operation
- Availability
- Server software
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UX User Experience
- Text readability
- Logic and convenience of the interface
- Visual defects
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Integration with programs
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Phones without a clickable link to start a call quickly
Links for Email addresses
Manifest validation.json with a list of favicons
Snippets of the site when sending links in social networks and instant messengers
Tag for specifying a large favicon
The BrowserConfig file
Apple touch bar icon for Mackbook pro
Favicon.ico file
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Vulnerabilities
- Code
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Server Settings
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Uploading all page files via HTTPS
Strict-https header for increased security
Private access to service files
Encrypted IPv6 connection
Enabled error display in the north
SSL certificate validity
HTTPS Availability
Redirects to protected
Vulnerabilities of a secure SSL connection
HTTP headers for increased security
- Third-party software
Blurry images
Blurred, pixelated and simply poor-quality images will greatly damage the impression of the site. Use large enough image files to make them look high-quality.
The appropriate image resolution depends on the size of the displayed area and the DPR of the screen. For example, if on a Full-HD monitor the picture is displayed in the area of 300×400 pixels, then for an Ultra-HD monitor you need to use a picture 2 times larger. Despite the fact that the site is displayed the same on both screens, Ultra-HD has a DPR of 2. That is, for each nominal pixel there are 2 real pixels of the monitor.
On mobile devices, the nominal page size can be 360 pixels, and the real screen resolution is 1080 pixels. Which corresponds to DPR equal to 3.
Mobile device screens can have a resolution of 360 to 424 pixels and a DPR of 2 to 4.5. That is, some mobile devices can display a picture of 424×4.5=1908 pixels. But such a picture will be very heavy and will greatly slow down the loading of the page.
We recommend focusing on the screen size of 414 pixels and DPR 2. This screen size is more than 95% of the screens of phone devices, and DPR is the optimal compromise between picture quality and site loading speed. We optimize the image for the following screens:
- Ultra-HD - 3840×2160 pixels.
- Full-HD - 1920×1080 pixels.
- HD - 1376×768 pixels.
- The phone is vertical - 414×896 pixels.
- The phone is horizontal - 896×414 pixels.
- The tablet is vertical - 768×1024 pixels.
- The tablet is horizontal - 1024×768 pixels.
Here is the code that uses the image of the desired size depending on the screen size:
“language-html
