There are three ways to selectively include CSS on a specific page: 1. Inline CSS, suitable for pages that are not frequently accessed or require unique styles; 2. Load external CSS files using JavaScript conditions, suitable for situations where flexibility is required; 3. Containment on the server side, suitable for scenarios using server-side languages. This approach can optimize website performance and maintainability, but requires balance of modularity and performance.

ThedifferentmethodsforincludingCSSinawebpageareinline,internal,andexternalCSS.1)InlineCSS:Easytoimplementbutleadstounmaintainablecode.2)InternalCSS:MoreorganizedthaninlinebutcanclutterHTML.3)ExternalCSS:Bestforlargerprojects,promotesmaintainabilityan

HTML, CSS and JavaScript are responsible for structure, style and dynamic functions in web development respectively. 1. HTML defines the web structure, 2. CSS is responsible for style and layout, 3. JavaScript provides dynamic interaction and functions.

In MongoDB, you can use the sort() method to sort documents in a collection. 1. Basic usage: Sort by specifying fields and sorting order (1 is ascending and -1 is descending), such as db.products.find().sort({price:1}). 2. Advanced usage: It can be sorted according to multiple fields, such as db.products.find().sort({category:1,price:-1}). 3. Performance optimization: Using indexing, avoiding oversorting and paging sorting can improve efficiency, such as db.products.createIndex({price:1}) and db.products.f

The overflow attribute handles overflow content by hiding, scrolling or automatically adjusting. The main values ??include 1. Hidden direct cropping; 2. Scroll always displays scroll bars; 3. Auto displays scroll bars as needed; 4. Overflow-x and overflow-y can control horizontal and vertical overflow respectively. 1. overflow:hidden is used to avoid overflow of content; 2. overflow:scroll is suitable for chat windows or fixed-size sidebars to keep the interface consistent; 3. overflow:auto is suitable for tables or user-generated content to achieve flexible scrolling; 4. Note when setting overflow-x and overflow-y independently

The future development direction of CSS is exciting, and its core lies in the fact that language is gradually meeting the needs of modern web development. 1. The native cascade layer provides better style priority control to reduce specific conflicts; 2. The sub-grid supports the alignment of nested elements with the parent container to avoid redundant code; 3. Container query allows components to adapt based on container size to promote true component design; 4.:has() selector can set the conditional style according to the state of the internal element to reduce JavaScript dependencies. These features mark the positive evolution of CSS in a more expressive and logical direction. Some functions have been available in modern browsers. Familiarity with them in advance will help future project practices.

CSS blocks page rendering because browsers view inline and external CSS as key resources by default, especially with imported stylesheets, header large amounts of inline CSS, and unoptimized media query styles. 1. Extract critical CSS and embed it into HTML; 2. Delay loading non-critical CSS through JavaScript; 3. Use media attributes to optimize loading such as print styles; 4. Compress and merge CSS to reduce requests. It is recommended to use tools to extract key CSS, combine rel="preload" asynchronous loading, and use media delayed loading reasonably to avoid excessive splitting and complex script control.

The method of using SQL includes the following steps: 1. Learn basic knowledge and master basic operations such as SELECT, INSERT, UPDATE and DELETE. 2. Understand the query function in depth and use JOIN for complex queries. 3. Optimize query performance and create indexes and other methods. 4. Master advanced usage, such as subqueries and views. 5. Avoid common errors, ensure correct syntax and logic, and optimize performance. 6. Follow best practices, keep SQL statements readable and maintain databases regularly.