Lessons
-
Introduction
-
SEO
- Snippet CTR
-
Indexing
-
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
-
Speed
-
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
- Caching
- Showing the first content
-
File size
-
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
-
Slow files
-
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
-
Number of network requests
-
Mobile adaptation
- Broken layout
- Compliance with guidelines
-
Software errors
- Code
- Mail operation
- Availability
- Server software
-
UX User Experience
- Text readability
- Logic and convenience of the interface
- Visual defects
-
Integration with programs
-
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
-
Vulnerabilities
- Code
-
Server Settings
-
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
The total size of all images on the page
The large total size of the images indicates several possible problems:
- Delayed loading technology is not used. You need to download only those images that are visible on the first screen. You need to upload the rest of the images at the time of request, when the user scrolls the page and they become visible.
- Missing minification. The opportunity to reduce the size of images without loss of quality using modern algorithms has not been used.
- You are using excessively large images. If the source file has a size of 1000 pixels, and it is displayed in a block of 150 pixels, then you should reduce the size of the source file.
In the example below, you can compare how adding the loading=”lazy” attribute affects the loading speed.
Demonstration
PHP code
HTML code
<?php
if(isset($_GET['t'])) {
// Симулируем задержку загрузки изображения, как для интернета 4G.
usleep(100000);
header('Content-Type: image/jpeg');
echo file_get_contents('photo.jpg');
die;
}
$mode = $_GET['mode'] ?? '';
?><!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
.product-grid {
display: grid;
grid-template-columns: 1fr 1fr 1fr 1fr;
font-size: 20px
}
.product-grid img {
width: 100%;
}
.product-grid .product {
position: relative;
}
.product-grid .time {
position: absolute;
left: 5px;
top: 5px;
background-color: #fff;
padding: 1px 4px;
}
.btn {
color: #000;
display: inline-block;
margin-bottom: 5px;
text-decoration: none;
padding: 5px 10px;
border: 1px solid #000;
border-radius: 5px;
}
.btn:hover {
background-color: #ddd;
}
.btn.active {
background-color: #000;
color: #fff;
}
</style>
<script>
// Функция, которая добавляет на изображение время окончания загрузки
function endLoading(el) {
var time = performance.now()/1000;
el.parentNode.insertAdjacentHTML("beforeend", '<div class="time">'+time+' с</div>');
}
window.addEventListener("load", (event) => {
document.querySelector('#page-load').innerHTML = 'Страница загрузилась (событие window.onload) за <b>'+(performance.now()/1000)+'с</b>.';
});
</script>
</head>
<body style="font-family: sans-serif;">
Режим: <a class="btn <?=$mode === '' ? 'active' : ''?>" href="./images_total_weight.php">Обычный режим</a> <a class="btn <?=$mode === 'lazy' ? 'active' : ''?>" href="./images_total_weight.php?mode=lazy">Режим отложенной загрузки</a>
<br />
<p>На странице 5.41 МБ изображений. При отложенной событие window.load отрабатывает сразу.</p>
<p id="page-load">Тут отобразится время загрузки страницы (вызова события window.onload)</p>
<div class="product-grid">
<?php for($i = 0; $i < 100;++$i) { ?>
<div class="product">
<img src="./images_total_weight.php?t=<?=microtime(true)+$i?>" <?=isset($_GET['mode']) && $_GET['mode'] === 'lazy' ? 'loading="lazy"' : ''?> onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<?php } ?>
</div>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
.product-grid {
display: grid;
grid-template-columns: 1fr 1fr 1fr 1fr;
font-size: 20px
}
.product-grid img {
width: 100%;
}
.product-grid .product {
position: relative;
}
.product-grid .time {
position: absolute;
left: 5px;
top: 5px;
background-color: #fff;
padding: 1px 4px;
}
.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>
<script>
// Функция, которая добавляет на изображение время окончания загрузки
function endLoading(el) {
var time = performance.now()/1000;
el.parentNode.insertAdjacentHTML("beforeend", '<div class="time">'+time+' с</div>');
}
window.addEventListener("load", (event) => {
document.querySelector('#page-load').innerHTML = 'Страница загрузилась (событие window.onload) за <b>'+(performance.now()/1000)+'с</b>.';
});
</script>
</head>
<body style="font-family: sans-serif;">
Режим: <a class="btn active" href="./images_total_weight.php">Обычный режим</a> <a class="btn " href="./images_total_weight.php?mode=lazy">Режим отложенной загрузки</a>
<br />
<p>На странице 5.41 МБ изображений. При отложенной событие window.load отрабатывает сразу.</p>
<p id="page-load">Тут отобразится время загрузки страницы (вызова события window.onload)</p>
<div class="product-grid">
<div class="product">
<img src="./images_total_weight.php?t=1783187000.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187001.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187002.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187003.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187004.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187005.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187006.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187007.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187008.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187009.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187010.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187011.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187012.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187013.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187014.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187015.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187016.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187017.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187018.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187019.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187020.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187021.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187022.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187023.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187024.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187025.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187026.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187027.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187028.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187029.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187030.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187031.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187032.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187033.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187034.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187035.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187036.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187037.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187038.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187039.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187040.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187041.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187042.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187043.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187044.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187045.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187046.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187047.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187048.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187049.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187050.0724" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187051.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187052.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187053.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187054.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187055.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187056.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187057.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187058.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187059.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187060.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187061.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187062.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187063.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187064.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187065.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187066.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187067.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187068.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187069.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187070.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187071.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187072.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187073.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187074.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187075.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187076.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187077.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187078.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187079.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187080.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187081.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187082.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187083.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187084.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187085.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187086.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187087.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187088.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187089.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187090.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187091.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187092.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187093.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187094.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187095.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187096.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187097.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187098.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
<div class="product">
<img src="./images_total_weight.php?t=1783187099.0725" onload="endLoading(this)" /><br />
Товар 1<br />
1000 руб.
</div>
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