Will CSS loading affect page loading speed?
Whether CSS loading will block page rendering is a common question. This article will explore in detail the impact of CSS loading on page rendering and provide specific code examples for demonstration.
First, we need to know how CSS loading affects page rendering. When the browser parses HTML, if it encounters an external CSS file, the browser will pause the parsing of the HTML and then start downloading the CSS file. Only after the CSS file is downloaded and parsed by the browser will the browser continue parsing the HTML. This means that CSS loading will block the rendering of the page.
To demonstrate this, we can create a simple HTML file that contains an external CSS file and a placeholder element. We will define a background color in the CSS file and apply this style on the placeholder element in the HTML. We'll then use the developer tools to view the rendering process of the page.
The HTML code is as follows:
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="styles.css">
</head>
<body>
<div class="placeholder"></div>
<script>
console.log("This is a placeholder element.");
</script>
</body>
</html>The CSS code (saved as styles.css) is as follows:
.placeholder {
width: 200px;
height: 200px;
background-color: red;
}If we open that HTML file and view the console output, we will notice To This is a placeholder element. will be output only after the CSS file is loaded. This shows that CSS loading does block the rendering of the page.
However, there is a situation where CSS loading does not block page rendering. If we place the CSS file in the <body> tag of HTML, and use the <link> tag's rel attribute value to be preload, the CSS file will be loaded asynchronously without blocking the rendering of the page. Here is an example of the modified HTML code:
<!DOCTYPE html>
<html>
<body>
<div class="placeholder"></div>
<link rel="preload" href="styles.css" as="style">
<link rel="stylesheet" href="styles.css">
<script>
console.log("This is a placeholder element.");
</script>
</body>
</html> In this example, we put the link to the CSS file in the tag and used < rel attribute of ;link> tag to asynchronously load CSS files. If we open the HTML file again and look at the console output, we'll notice that This is a placeholder element. is output before the CSS file is loaded. This means that the rendering of the page will not be blocked by the loading of CSS files.
To summarize, CSS loading will block the rendering of the page unless we use asynchronous loading. Asynchronous loading of CSS files can be done by placing the <link> tag inside the tag and using the preload## of the rel attribute # value to achieve.
The above is the detailed content of Will CSS loading affect page loading speed?. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1386
52
How to render orthogonal top view in Kujiale_Tutorial on rendering orthogonal top view in Kujiale
Apr 02, 2024 pm 01:10 PM
1. First open the design plan to be rendered in Kujiale. 2. Then open top view rendering under the rendering menu. 3. Then click Orthogonal in the parameter settings in the top view rendering interface. 4. Finally, after adjusting the model angle, click Render Now to render the orthogonal top view.
Effectively deal with situations where jQuery .val() doesn't work
Feb 20, 2024 pm 09:36 PM
Title: Methods and code examples to solve the problem that jQuery.val() does not work. In front-end development, jQuery is often used to operate page elements. Among them, getting or setting the value of a form element is one of the common operations. Usually, we use jQuery's .val() method to operate on form element values. However, sometimes you encounter situations where jQuery.val() does not work, which may cause some problems. This article will introduce how to effectively deal with jQuery.val(
How to read html
Apr 05, 2024 am 08:36 AM
Although HTML itself cannot read files, file reading can be achieved through the following methods: using JavaScript (XMLHttpRequest, fetch()); using server-side languages (PHP, Node.js); using third-party libraries (jQuery.get() , axios, fs-extra).
c# What is delegation and what problem does it solve?
Apr 04, 2024 pm 12:42 PM
Delegation is a type-safe reference type used to pass method pointers between objects to solve asynchronous programming and event handling problems: Asynchronous programming: Delegation allows methods to be executed in different threads or processes, improving application responsiveness. Event handling: Delegates simplify event handling, allowing events such as clicks or mouse movements to be created and handled.
Understand the implementation methods and advantages of blocking in Go language
Mar 24, 2024 am 08:36 AM
Go language is a programming language with very powerful concurrency features. It uses the concept of goroutine to achieve concurrency, and also provides a wealth of tools and methods to deal with blocking. In the Go language, the implementation methods and advantages of blocking are important things we need to understand. This article will introduce the implementation method of blocking in Go language and its advantages, and provide specific code examples to help readers better understand. Implementation methods of blocking In the Go language, blocking can be implemented in a variety of ways, including channels, mutual
How to prevent page redirection in WordPress?
Mar 05, 2024 am 09:33 AM
How to prevent page redirection in WordPress? In website development, sometimes we want to implement a page non-jump setting in WordPress, that is, during certain operations, the page content can be updated without refreshing the entire page. This improves user experience and makes the website smoother. Next, we will share how to implement the page non-jump setting in WordPress and provide specific code examples. First, we can use Ajax to prevent the page from jumping. Ajax
Sharing of PHP search function optimization tips
Mar 06, 2024 am 11:12 AM
PHP search function has always been a very important part of website development, because users often use the search box to find the information they need. However, many websites have problems such as low efficiency and inaccurate search results when implementing search functions. In order to help you optimize PHP search function, this article will share some tips and provide specific code examples. 1. Use full-text search engines. Traditional SQL databases are less efficient when processing large amounts of text content. Therefore, it is recommended to use full-text search engines, such as Elasticsearch, Solr, etc.
How to introduce external js into html
Apr 11, 2024 am 06:18 AM
To include an external JS file in HTML, use the <script> tag and specify the URL of the file to load. You can also specify type, defer, or async attributes to control how loading and execution occur. Typically, the <script> tag should be placed at the bottom of the <body> section to avoid blocking page rendering.
