The role of the invalid selector is to set a specific style when an illegal value is entered in the form element. The purpose is to remind the user that the entered value is incorrect.
The :invalid selector in CSS is mainly used Sets the specified style when the value in the form element is illegal.
【Recommended course: CSS Tutorial】
Example: When the user input is not a legal value, the style will change to a red border
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style>
input:invalid
{
border:2px solid red;
}
</style>
</head>
<body>
<input type="email" value="" />
<p>请输入合法 e-mail 地址，查看样式变化。</p>
</body>
</html>Rendering:
The above is the detailed content of What is the use of invalid selector?. For more information, please follow other related articles on the PHP Chinese website!
Demystifying Screen Readers: Accessible Forms & Best PracticesMar 08, 2025 am 09:45 AMThis is the 3rd post in a small series we did on form accessibility. If you missed the second post, check out "Managing User Focus with :focus-visible". In
Create a JavaScript Contact Form With the Smart Forms FrameworkMar 07, 2025 am 11:33 AMThis tutorial demonstrates creating professional-looking JavaScript forms using the Smart Forms framework (note: no longer available). While the framework itself is unavailable, the principles and techniques remain relevant for other form builders.
Adding Box Shadows to WordPress Blocks and ElementsMar 09, 2025 pm 12:53 PMThe CSS box-shadow and outline properties gained theme.json support in WordPress 6.1. Let's look at a few examples of how it works in real themes, and what options we have to apply these styles to WordPress blocks and elements.
Working With GraphQL CachingMar 19, 2025 am 09:36 AMIf you’ve recently started working with GraphQL, or reviewed its pros and cons, you’ve no doubt heard things like “GraphQL doesn’t support caching” or
Making Your First Custom Svelte TransitionMar 15, 2025 am 11:08 AMThe Svelte transition API provides a way to animate components when they enter or leave the document, including custom Svelte transitions.
Classy and Cool Custom CSS Scrollbars: A ShowcaseMar 10, 2025 am 11:37 AMIn this article we will be diving into the world of scrollbars. I know, it doesn’t sound too glamorous, but trust me, a well-designed page goes hand-in-hand
Show, Don't TellMar 16, 2025 am 11:49 AMHow much time do you spend designing the content presentation for your websites? When you write a new blog post or create a new page, are you thinking about
What the Heck Are npm Commands?Mar 15, 2025 am 11:36 AMnpm commands run various tasks for you, either as a one-off or a continuously running process for things like starting a server or compiling code.
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
AI Hentai Generator
Generate AI Hentai for free.
Hot Article
Hot Tools
PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool
DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software
SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.
Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.
MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.
