Inthisarticle,wewilldiscusshowtodeclareacustomattributeinHTML.CustomattributescanbeusefulinHTMLwhenyouwanttostoresomeadditionalinformationthatisnotpartofthestandardHTMLattributes.ItallowsformoreflexibilityandcustomizationinHTMLandcanhelpmakeyourcodem

This article will take you through CSS variables, talk about how CSS variables work, and introduce how to use inline CSS variables to improve the efficiency of smart layout. I hope it will be helpful to everyone!

The scope of CSS custom properties depends on the context of their declaration, global variables are usually defined in :root, while local variables are defined within a specific selector for componentization and isolation of styles. For example, variables defined in the .card class are only available for elements that match the class and their children. Best practices include: 1. Use: root to define global variables such as topic color; 2. Define local variables inside the component to implement encapsulation; 3. Avoid repeatedly declaring the same variable; 4. Pay attention to the coverage problems that may be caused by selector specificity. Additionally, CSS variables are case sensitive and should be defined before use to avoid errors. If the variable is undefined or the reference fails, the fallback value or default value initial will be used. Debug can be done through the browser developer

The html5 custom attribute "data-*" is used to store custom data applied behind a private page, and the custom data can give the page a better interactive experience (no need to use Ajax or go to the server to query data), the syntax " <element data-*="Specify attribute value (a string)">"; "data-*" attribute consists of two parts: 1. The attribute name should not contain uppercase letters, and there must be at least one character after "data-" ;2. Attribute value, the value can be any string.

CustomAttributes are mechanisms used in C# to attach metadata to code elements. Its core function is to inherit the System.Attribute class and read through reflection at runtime to implement functions such as logging, permission control, etc. Specifically, it includes: 1. CustomAttributes are declarative information, which exists in the form of feature classes, and are often used to mark classes, methods, etc.; 2. When creating, you need to define a class inherited from Attribute, and use AttributeUsage to specify the application target; 3. After application, you can obtain feature information through reflection, such as using Attribute.GetCustomAttribute();

CSS variables improve style maintenance and theme management by defining reusable values. Its core advantages include: 1. Reduce duplication and improve consistency by centrally defining style values; 2. Support dynamic coverage to achieve simple and efficient multi-theme switching; 3. Avoid common traps such as inconsistent naming, overuse, etc. Developers should define global variables in:root, and use scope and fallback values ??to enhance flexibility and readability, while dynamic adjustments are combined with JavaScript to improve user experience.

The core of using CSS variables to achieve topic switching is to define the basic variables and organize the topic structure, and dynamically switch through class names or attributes. The steps are as follows: 1. Define basic variables such as colors, fonts, etc. in root; 2. Create classes that cover variables for different themes (such as dark and light colors); 3. Call variables using var() in CSS rules; 4. Switch class names or attributes through JavaScript to achieve theme changes; 5. Extend variables to font size, rounded corners, shadows and other style attributes. This clear structure and easy maintenance lies in reasonable naming and scope control.

CSS custom attributes (i.e. CSS variables) improve development efficiency by storing and reusing style values. The core usage methods include: 1. Use the --variable name syntax to define in:root or specific selector; 2. Reference variables through the var (--variable name, default value) function; 3. Can dynamically update the variable values, support theme switching, responsive design and other scenarios. Their inheritance and cascade rules are consistent with ordinary CSS properties and can be modified through JavaScript runtime to achieve user preferences or dynamic style adjustments.