Which is the head tag in html

Event delegation is a technique that uses the event bubble mechanism to hand over the event processing of child elements to the parent element. It reduces memory consumption and supports dynamic content management by binding listeners on parent elements. The specific steps are: 1. Binding event listeners to the parent container; 2. Use event.target to determine the child elements that trigger the event in the callback function; 3. Execute the corresponding logic based on the child elements. Its advantages include improving performance, simplifying code maintenance and adapting to dynamically added elements. When using it, you should pay attention to event bubble restrictions, avoid excessive centralized monitoring, and reasonably select parent elements.

Used to inline code snippets, while retaining the formatted blocks of text. 1. Applicable to small segments of code in sentences, displayed in monospace fonts by default, without retaining spaces and line breaks; 2. Keep all whitespace characters and line breaks, suitable for multi-line code or text that needs to be kept in format; 3. Both can be used in combination to obtain semantic and format reservations at the same time; 4. Usually, custom CSS styles are required to enhance the appearance.

To solve the problem of content overflow in web pages, you can use the CSS attribute to control it. 1. Use the overflow attribute to control the display of overflow content, such as overflow:hidden hides overflow content, and overflow:auto adds scroll bars when needed; 2. Set max-width and max-height to prevent too large images or media elements from causing misalignment in layout, and combine object-fit to maintain visual consistency; 3. Use min-width and min-height to avoid too small containers affecting readability and interactivity; 4. Use text-overflow:ellipsis to display ellipsis when the text is too long to keep the interface neat. These methods can

The reasons for using Storybook to build a component library include supporting mainstream frameworks, providing isolation of the publishing environment, and automatically generating documents; the specific steps are installing Storybook, writing components and stories files, and adding plug-in extension functions; it is recommended to start from basic components, gradually improve the process and pay attention to details such as naming specifications, organizational structures, logical reuse, interactive testing and document export.

Vite greatly improves the development experience through native ES modules and on-demand compilation; 1. Use the browser natively to support ESModules, load and compile files on demand, achieving fast cold start and smooth hot updates; 2. Supports a variety of frameworks such as Vue, React, Preact, etc., which are out of the box, and automatically configures the environment for initialization commands; 3. Production and construction is based on Rollup, with optimization capabilities such as code segmentation, Tree-shaking, dynamic import, etc., and the package size is smaller; 4. The plug-in system is compatible with Rollup plug-ins, and the ecosystem is mature, and functions can be easily expanded.

The call stack is a structure that manages the order of call of function by JavaScript, and the memory heap is used to store variables and objects. JS uses the call stack to record the execution order of functions. Each time a function is called, it is pushed to the top of the stack and pops up after execution; if the nesting is too deep or recursively infinite, it will cause stack overflow. The memory heap stores complex data such as objects, and variables only store reference addresses; the basic types are stored directly on the stack. The two work together to complete the operation: if the array is defined in a function, the variable name is on the stack and the array content is on the heap. The function is executed, local variables are destroyed, and objects in the heap are not referenced to be recycled. Understanding this mechanism can help avoid stack overflow and memory leaks.

Integrating payment gateways at the front end requires ensuring a secure and smooth experience. The core methods include using a tokenized mechanism, choosing a suitable integration method, processing payment feedback, and paying attention to cross-domain adaptation with mobile terminals. 1. Use the tokenization mechanism to ensure safety, collect information through the SDK to generate tokens, and complete deductions to avoid contact with sensitive data. 2. The integrated method can choose redirect payment page, embedded payment form or custom UI HostedFields. StripeElements and other solutions are recommended to take into account experience and security. 3. Improve payment feedback logic, distinguish between success, failure, cancellation and other statuses and give prompts to prevent repeated submissions. 4. Pay attention to cross-domain compatibility and mobile adaptation to ensure responsive layout and fast payment support.

React's coordination mechanism improves performance by comparing the virtual DOM differences. The core is to update only the changing parts, not replace them in full. 1. The virtual DOM copy is separated from the real DOM, and a new tree is generated when the state changes and diff is compared; 2. The key attribute is crucial in list rendering. The use of a unique stable identifier (such as id) can help React correctly identify the element identity; 3. To reduce unnecessary rendering, React.memo, useCallback, useMemo or shouldComponentUpdate can be used to control the update logic of the component. Understanding this mechanism can help write more efficient React applications.