Set background gradients of different colors using the transparency of the background gradient_html/css_WEB-ITnose

Native lazy loading is a built-in browser function that enables lazy loading of pictures by adding loading="lazy" attribute to the tag. 1. It does not require JavaScript or third-party libraries, and is used directly in HTML; 2. It is suitable for pictures that are not displayed on the first screen below the page, picture gallery scrolling add-ons and large picture resources; 3. It is not suitable for pictures with first screen or display:none; 4. When using it, a suitable placeholder should be set to avoid layout jitter; 5. It should optimize responsive image loading in combination with srcset and sizes attributes; 6. Compatibility issues need to be considered. Some old browsers do not support it. They can be used through feature detection and combined with JavaScript solutions.

srcset and sizes are key properties for HTML implementation of responsive images. srcset provides multiple image sources and their width or pixel density, such as 400w and 800w, and the browser selects the appropriate image accordingly; sizes defines the display width of the image under different screen widths, such as (max-width: 600px)100vw, 50vw, so that the browser can more accurately match the image size. In actual use, you need to prepare multi-size pictures, clearly named, design layout in accordance with media query, and test the performance of the equipment to avoid ignoring sizes or unit errors, thereby saving bandwidth and improving performance.

The main difference is that textarea supports multiple lines of text input, while inputtext is only available in a single line. 1. Use inputtype="text" to be suitable for short and single-line user input, such as username, email address, etc., and can set maxlength to limit the number of characters. The browser provides automatic filling function, making it easier to uniformly style across browsers; 2. Use textarea for scenarios that require multiple lines of input, such as comment boxes, feedback forms, support line breaks and paragraphs, and can control the size through CSS or disable the adjustment function. Both support form features such as placeholders and required fills, but textarea defines the size through rows and cols, and input uses the size attribute.

It is a block-level element, used to divide large block content areas; it is an inline element, suitable for wrapping small segments of text or content fragments. The specific differences are as follows: 1. Exclusively occupy a row, width and height, inner and outer margins can be set, which are often used in layout structures such as headers, sidebars, etc.; 2. Do not wrap lines, only occupy the content width, and are used for local style control such as discoloration, bolding, etc.; 3. In terms of usage scenarios, it is suitable for the layout and structure organization of the overall area, and is used for small-scale style adjustments that do not affect the overall layout; 4. When nesting, it can contain any elements, and block-level elements should not be nested inside.

To get started with HTML quickly, you only need to master a few basic tags to build a web skeleton. 1. The page structure is essential, and, which is the root element, contains meta information, and is the content display area. 2. Use the title. The higher the level, the smaller the number. Use tags to segment the text to avoid skipping the level. 3. The link uses tags and matches the href attributes, and the image uses tags and contains src and alt attributes. 4. The list is divided into unordered lists and ordered lists. Each entry is represented and must be nested in the list. 5. Beginners don’t have to force memorize all tags. It is more efficient to write and check them while you are writing. Master the structure, text, links, pictures and lists to create basic web pages.

To achieve a basic pop-up effect, you need to follow the following steps: 1. Structure: Use HTML to create trigger buttons, mask layer and pop-up content area; 2. Style: Set default hidden, centered layout, mask background and close button styles through CSS; 3. Interaction: Use JavaScript to bind click events to control pop-up display and hide, and can expand the ESC key closing function; 4. Optimization: Add CSS animation to improve user experience. The entire process does not require a third-party library, which is suitable for quickly realizing basic pop-up functions.

Webworkers are independent threads running in the browser background, used to perform time-consuming tasks without blocking the user interface. They are implemented through JavaScript files and are started by scripts in HTML pages, but once run, they are separated from the main thread. 1. Webworkers cannot directly access the DOM to ensure page stability; 2. They realize secure communication with the main thread through postMessage() and onmessage; 3. It is suitable for processing CPU-intensive tasks such as images, complex computing, data analysis; 4. It supports some APIs such as setTimeout, fetch and IndexedDB; 5. When using it, you need to pay attention to debugging difficulties, memory usage, cross-domain restrictions and other issues.

ShadowDOM is a technology used in web component technology to create isolated DOM subtrees. 1. It allows the mount of an independent DOM structure on ordinary HTML elements, with its own styles and behaviors, and does not affect the main document; 2. Created through JavaScript, such as using the attachShadow method and setting the mode to open; 3. When used in combination with HTML, it has three major features: clear structure, style isolation and content projection (slot); 4. Notes include complex debugging, style scope control, performance overhead and framework compatibility issues. In short, ShadowDOM provides native encapsulation capabilities for building reusable and non-polluting UI components.