Using HTML `textarea` `rows` and `cols`

How to make HTML mail templates with good compatibility? First, you need to build a structure with tables to avoid using div flex or grid layout; secondly, all styles must be inlined and cannot rely on external CSS; then the picture should be added with alt description and use a public URL, and the buttons should be simulated with a table or td with background color; finally, you must test and adjust the details on multiple clients.

class, id, style, data-, and title are the most commonly used global attributes in HTML. class is used to specify one or more class names to facilitate style setting and JavaScript operations; id provides unique identifiers for elements, suitable for anchor jumps and JavaScript control; style allows for inline styles to be added, suitable for temporary debugging but not recommended for large-scale use; data-properties are used to store custom data, which is convenient for front-end and back-end interaction; title is used to add mouseover prompts, but its style and behavior are limited by the browser. Reasonable selection of these attributes can improve development efficiency and user experience.

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.

Using HTML tags, you can use the href attribute to realize page jump, open new windows, positioning within pages and email and phone link functions. 1. Basic usage: Specify the target address through href, such as accessing a web page; 2. Open a new window: add target="_blank" and rel="noopener" attributes; 3. Jump within the page: combine id and # symbol to achieve anchor point positioning; 4. Email phone link: use mailto: or tel: protocol to trigger system applications.

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.

When using HTML and tags, the core difference is semantics: used to organize content blocks related to topics, and to wrap content that can exist independently. 1. Applicable to blocks with titles, logically divided within the page, such as product page specifications, comments and related product parts; 2. Applicable to content that can be reused such as blog posts, news stories or comments, such as each independent article on the homepage of the blog or every comment section; 3. Both improve accessibility and SEO. Correct use helps screen readers navigation and search engines understand the page structure. Although there is no visual difference, semantic clarity is better than ordinary use.

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.