HTML provides not only plain paragraph tags, but six separate header tags to indicate headings of various sizes and thicknesses. Enumerated as heading 1 through heading 6, heading 1 has the largest and thickest text while heading 6 is the smallest and thinnest, down to the paragraph level. This topic details proper usage of these tags.

Section 3.1: Using Headings

Headings can be used to describe the topic they precede and they are defined with the <h1> to <h6> tags. Headings support all the global attributes.

<h1> defines the most important heading.

<h6> defines the least important heading.

Defining a heading:

<h1>Heading 1</h1>

<h2>Heading 2</h2>

<h3>Heading 3</h3>

<h4>Heading 4</h4>

<h5>Heading 5</h5>

<h6>Heading 6</h6>

Correct structure matters

Search engines and other user agents usually index page content based on heading elements, for example to create a table of contents, so using the correct structure for headings is important.

In general, an article should have one h1 element for the main title followed by h2 subtitles – going down a layer if necessary. If there are h1 elements on a higher level they shoudn't be used to describe any lower level content.

Example document (extra intendation to illustrate hierarchy):

<h1>Main title</h1>

<p>Introduction</p>

<h2>Reasons</h2>

<h3>Reason 1</h3>

<p>Paragraph</p>

<h3>Reason 2</h3>

<p>Paragraph</p>

<h2>In conclusion</h2>

<p>Paragraph</p>