Lessons
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Introduction
-
SEO
- Snippet's clickability in search engines
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Indexing
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Headings H1-H6
Images have the "alt" attribute.
The Title attribute of links
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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Reduce the number of network requests
-
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
- Configure the server
- Speed up the display of the first content
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Reduce the size of graphic files
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Minification of the embedded JavaScript code of the page
Minification of the embedded CSS code of the page
Minification of images without loss of quality
The total size of all images on the page
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
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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Server performance
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HTML code generation time
Optimal time to download files from the server
Time to download files from the server under load
- Fix the locks
- Reduce the amount of code
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Reduce the number of network requests
- Mobile adaptation
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Software errors
- Code
- Mail operation
- Availability
- Server Settings
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Convenience
- Text readability
- Interface
- Visual defects
- Interaction with other programs
- Image Favicon
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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 services
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>