Understand HTML global attributes. Which attributes are not global attributes?

Understand HTML global attributes. Which attributes are not global attributes?

HTML global attributes are attributes that apply to all HTML elements and are universal and versatile. They provide common control and adjustment of elements and can be used throughout the HTML document. However, not all properties are global properties, and this article will introduce some common properties that are not global properties.

1. id attribute: The id attribute is used to provide a unique identifier for an HTML element. It is usually used as a selector in JavaScript and CSS to select specific HTML elements for manipulation or style adjustment. The id attribute is not a global attribute because it only applies to a single element and cannot be applied to multiple elements.
2. class attribute: The class attribute is used to specify one or more class names for HTML elements. It is similar to the id attribute and is used to select, manipulate and style HTML elements, but can be applied to multiple elements. Class names are often used to select a group of related HTML elements and apply the same or similar styles to them. Because the class attribute only affects a specific set of elements, it is not a global attribute.
3. style attribute: The style attribute is used to specify inline styles directly in HTML elements. It can specify specific style rules for elements, such as color, font size, borders, etc. The style attribute has a higher style priority, but it only applies to a single element and cannot be applied to all elements. Therefore, the style attribute is not a global attribute.
4. data- attribute: The data- attribute is a new custom data attribute in HTML5, which is used to store custom data related to elements. It can create custom attributes on HTML elements and assign custom values ​​to them. This custom data can be accessed and manipulated via JavaScript or CSS. The data-* attributes are also not global attributes, because they are customized by developers according to their needs and are not universally applicable.

In addition to the common properties mentioned above that are not global properties, there are also some properties related to specific elements that are not global properties. For example, the src attribute is used to specify the source file of media elements such as pictures, audio or video; the href attribute is used to specify the target URL address of the link element; the action attribute is used to specify the submission address of the form element, etc. These attributes only have meaning and effect through specific HTML elements, so they are not global attributes.

In summary, HTML global attributes are attributes that apply to all HTML elements and are universal and versatile. The id attribute, class attribute, style attribute, data-* attribute, etc. are not global attributes. They are attributes used for the identification, style and custom data of specific elements. Understanding and distinguishing these different types of attributes helps us better understand and apply HTML markup language.

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