Description
The HTML element <h1> to <h6> are used to define headings.
There are six heading elements <h1>, <h2>, <h3>, <h4>, <h5>, and <h6>.
- The 
<h1>element is the most important heading and displays bigger than others - The 
<h6>element is the least important heading and displays smaller than others 
Here are some suggestions while using headings on a web page.
- Always define only one 
<h1>element to define the page heading, which is helpful for SEO - Always use headings sequentially on a page like 
<h1>for the main heading,<h2>for its sub-heading,<h3>for the next level sub-heading, and so on. 
The below table summarizes its usage.
| Usage Details | |
| Placement | It is displayed as a Block element. | 
| Contents | It can contain Inline elements and text. | 
| Tags | Both opening and closing tags are required. | 
| Versions | HTML 2,3.2, 4, 4.01, 5 | 
Syntax
Here is the basic syntax of the <h1> to <h6> elements.
<h1>...</h1>
<h2>...</h2>
<h3>...</h3>
<h4>...</h4>
<h5>...</h5>
<h6>...</h6>
Examples
Element <hgroup> used to define web page header with navigation links.
<h1>Heading level 1</h1>
<h2>Heading level 2</h2>
<h3>Heading level 3</h3>
<h4>Heading level 4</h4>
<h5>Heading level 5</h5>
<h6>Heading level 6</h6>
Attributes
The following table shows the list of supported and unsupported attributes for the heading elements.
| Attribute Type | Details | 
| Element-Specific Attributes | The tags <h1> to <h6> doesn't have any element-specific attributes. | 
| Global Attributes | Like all other HTML tags, the tags <h1> to <h6> supports the HTML Global Attributes. | 
| Event Attributes | The tags <h1> to <h6> also supports the HTML Event Attributes. | 
Here is a list of attributes that are specific to the heading elements.
| Attribute | Value | Description | 
align | 
left, right, center, justify | Obsolete and Not to be used. Aligns the content inside a heading element.  | 
Browser Compatibility
The tags <h1> to <h6> are supported in all modern browsers.
- Google Chrome 1+
 - Internet Explorer or Edge 2+
 - Firefox 1+
 - Apple Safari 1+
 - Opera 4+