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
- Compliance with guidelines
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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
HTML code generation time
The first file that the user receives when visiting the page is HTML code. Only after that the browser downloads the rest of the files.
It is considered the norm when HTML is loaded before 0.3 seconds.
Also, the faster the HTML code of the page is generated, the less computing resources are spent on its generation. Consequently, the load on the server decreases. So, it will be able to withstand a large peak load. For example, generating a page in 0.25 seconds, the server will be able to issue 4 pages per second. But if you speed up page generation to 0.1 seconds, then the server will already be able to serve 10 visitors per second.
The key tools to speed up the page are:
- Caching. Moreover, it is best to use in-memory caching technology like memcache. It demonstrates impressive acceleration.
- Page profiling and optimization of “bottlenecks”. This is when the programmer places timestamps throughout the code. If too much time passes between adjacent labels, it means that the code between them is not optimal and there is potential for optimization.
Finding and speeding up slow sections of code is a process that requires perseverance and high professionalism. A programmer can study the code for several days and fix only 1 line. The task of speeding up is much more difficult than writing new functionality.
Demonstration of the difference in page loading time with different HTML code loading times:
<?php
if(isset($_GET['delay'])) {
switch($_GET['delay']) {
case '0.1':
usleep(100000);
break;
case '0.5':
usleep(500000);
break;
case '1':
usleep(1000000);
break;
default:
break;
}
}
$delay = $_GET['delay'] ?? '';
?><!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
.btn {
color: #000;
display: inline-block;
margin-bottom: 5px;
text-decoration: none;
padding: 5px 10px;
border: 1px solid #000;
border-radius: 5px;
}
.btn:hover {
background-color: #ddd;
}
.btn.active {
background-color: #000;
color: #fff;
}
</style>
</head>
<body style="font-family: sans-serif;">
<a class="btn <?=$delay === '' ? 'active' : ''?>" href="./html_loading_too_long.php">Без задержки</a>
<a class="btn <?=$delay === '0.1' ? 'active' : ''?>" href="./html_loading_too_long.php?delay=0.1">Задержка 0.1 секунда</a>
<a class="btn <?=$delay === '0.5' ? 'active' : ''?>" href="./html_loading_too_long.php?delay=0.5">Задержка 0.5 секун</a>
<a class="btn <?=$delay === '1' ? 'active' : ''?>" href="./html_loading_too_long.php?delay=1">Задержка 1 секунда</a>
<h1>HTML загружен</h1>
<script>
var buttons = document.querySelectorAll('.btn');
for(var i = 0; i < buttons.length; ++i)
// Сигнализируем о начале загрузки страницы
buttons[i].addEventListener("click", function() {
document.write('<h1>Загружаем страницу</h1>');
});
</script>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
.btn {
color: #000;
display: inline-block;
margin-bottom: 5px;
text-decoration: none;
padding: 5px 10px;
border: 1px solid #000;
border-radius: 5px;
}
.btn:hover {
background-color: #ddd;
}
.btn.active {
background-color: #000;
color: #fff;
}
</style>
</head>
<body style="font-family: sans-serif;">
<a class="btn active" href="./html_loading_too_long.php">Без задержки</a>
<a class="btn " href="./html_loading_too_long.php?delay=0.1">Задержка 0.1 секунда</a>
<a class="btn " href="./html_loading_too_long.php?delay=0.5">Задержка 0.5 секун</a>
<a class="btn " href="./html_loading_too_long.php?delay=1">Задержка 1 секунда</a>
<h1>HTML загружен</h1>
<script>
var buttons = document.querySelectorAll('.btn');
for(var i = 0; i < buttons.length; ++i)
// Сигнализируем о начале загрузки страницы
buttons[i].addEventListener("click", function() {
document.write('<h1>Загружаем страницу</h1>');
});
</script>
</body>
</html>