The key to using radio buttons in HTML5 is to understand how they work and correctly organize the code structure. 1. The name attribute of each radio button must be the same to achieve mutually exclusive selection; 2. Use label tags to improve accessibility and click experience; 3. It is recommended to wrap each option in a div or label to enhance structural clarity and style control; 4. Set default selections through the checked attribute; 5. The value value should be concise and meaningful, which is convenient for form submission processing; 6. The style can be customized through CSS, but the function needs to be ensured to be normal. Mastering these key points can effectively avoid common problems and improve the effectiveness of use.

The core difference between localStorage and sessionStorage lies in data persistence and scope. 1. Data life cycle: localStorage data is stored for a long time unless manually cleared, and sessionStorage data is cleared after closing the tab; 2. Scope difference: localStorage is shared among all tabs on the same website, and sessionStorage is stored independently; 3. Usage scenario: localStorage is suitable for saving long-term data such as user preferences and login status, sessionStorage is suitable for temporary form data or single session process; 4. API consistency: two operation methods

Yes, it is part of HTML5, but its use has gradually decreased and is controversial. Used to combine the main title with the subtitle so that only the highest level of titles are identified in the document outline; for example, the main title and subtitle can be wrapped in to indicate that they are only auxiliary titles rather than independent chapter titles; however, reasons why they are no longer widely used include: 1. The browser and screen readers are inconsistent support for them, 2. There are simpler alternatives such as using CSS to control styles, 3. The HTML document outline algorithm is not widely supported; despite this, it can still be considered in websites or documents with high semantic requirements; while in most cases, developers tend to use a single, manage styles through CSS and maintain clear title levels.

Declare the document as HTML5 to avoid the browser from entering weird mode; 2. Define the root element and specify the language to improve accessibility and SEO; 3. It includes ensuring correct character encoding, implementing responsive design, and setting page title; 4. Place all visible content, optionally add CSS, favicon and JavaScript links; this template is complete and compatible with modern browsers, and is suitable for any new HTML file.

Server-SentEvents (SSE) is a technology in HTML5 that implements server pushing data to clients in real time, and is suitable for stock market, notification systems and other scenarios. It is based on the HTTP protocol, and remains open after establishing a connection. The server can send updates at any time, supporting automatic reconnection and standard data formats. The front-end receives data by creating an EventSource object and listening to message events. The backend needs to set the correct MIME type (text/event-stream) and keep the connection open and continuously output data stream. When using it, you need to pay attention to cross-domain issues, connection timeouts, browser compatibility and intermediate layer restrictions.

The Schema.org tag helps search engines understand the structured data format of web page content through semantic tags (such as item scope, item type, itemprop); it can be used to define custom vocabulary, methods include extending existing types or using additionalType to introduce new types; in actual applications, keeping the structure clear, using official attributes first, testing code validity, and ensuring that custom types are accessible; precautions include accepting partial support, avoiding spelling errors, and choosing a suitable format such as JSON-LD.

HTML5 tags are used to wrap the main content of a web page. The content should be unique to the page and not included in other page shared parts such as header, footer or navigation menus. It belongs to the semantic element, which helps browsers and assistive technologies understand website structure. 1. It should contain content that directly associates the core purpose of the page, such as article text, page-specific forms, interactive widgets bound to the current page, and media files that are the focus of the page; 2. Use can improve accessibility and SEO, including better screen reader support, clearer DOM structure and enhanced SEO through semantic clarity; 3. It should not be used in components such as footer, sidebar or pop-ups, nor should it be used for content that is repeated across pages, and can only be used once per page; 4. If the page does not have it

HTML5parsershandlemalformedHTMLbyfollowingadeterministicalgorithmtoensureconsistentandrobustrendering.1.Formismatchedorunclosedtags,theparserautomaticallyclosestagsandadjustsnestingbasedoncontext,suchasclosingabeforeaandreopeningitafterward.2.Withimp