Explore the definition and role of HTML global attributes

Explore the definition and role of HTML global attributes

HTML (Hypertext Markup Language) is a markup language used to describe the structure and content of web pages. In HTML, global attributes are attributes that apply to all HTML elements and have a global effect. This article will explore the definition and role of HTML global attributes and provide specific code examples.

1. class

The class attribute is used to define one or more class names for HTML elements. Class names are used to identify or combine elements, and elements can be manipulated and controlled through CSS style sheets and JavaScript. By adding class attributes to elements, styles can be reused and maintained.

Code example:

<div class="container">
  <p class="text">Hello, World!</p>
</div>

2. id

The id attribute is used to define a unique identifier for an HTML element. Through the id attribute, specific HTML elements can be easily manipulated and controlled in JavaScript. In an HTML document, the value of the id attribute must be unique.

Code example:

<div id="header">This is the header</div>

3. style

The style attribute is used to specify inline styles for HTML elements. Inline styles are CSS styles written directly on HTML tags, which can override the settings of external style sheets or internal styles. Through the style attribute, styles can be defined individually for specific elements.

Code example:

<p style="color: blue; font-size: 16px;">This is a blue paragraph with font size of 16px</p>

4. title

The title attribute is used to provide additional prompt information for HTML elements. When the mouse hovers over an element with a title attribute, the value of the title attribute is displayed. The title attribute is applicable to most HTML elements and can increase user experience and page accessibility.

Code example:

<button title="Click me!">Submit</button>

5. tabindex

The tabindex attribute is used to control the focus order of HTML elements. When the user uses the Tab key to navigate on the page, the focus of the HTML element will switch in the order of the value of the tabindex attribute. The value of the tabindex attribute can be a positive integer, 0 or -1.

Code example:

<input type="text" tabindex="1">
<input type="checkbox" tabindex="2">
<input type="submit" tabindex="3">

6. data-*

data-* attributes are used to define custom data attributes for HTML elements. These custom data attributes can be used in JavaScript to store some element-related data to facilitate subsequent operations and processing.

Code example:

<div data-user-id="123" data-user-name="John Doe">User Information</div>

7. lang

The lang attribute is used to specify the language of the HTML element. Through the lang attribute, different languages ​​can be set for each HTML element to achieve support and internationalization of multi-language websites.

Code example:

<p lang="en">Hello, World!</p>
<p lang="zh">你好，世界！</p>

The above are the definitions and functions of some commonly used HTML global attributes. By rationally using these global attributes, the quality, maintainability and accessibility of web pages can be improved. I hope this article can give everyone a deeper understanding of HTML global attributes.

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