Using the HTML heading tags -- H1 through H6 -- to reveal the hierarchical structure of a web page helps foster search engine optimization (SEO).
A hierarchical structure that includes a main topic and discreet subsections, all marked off by correctly sized headings, shows readers and search engines alike what information is important and what information provides supporting details. Readers can more easily scan the content for the information they want, and search engines can more accurately categorize the page's content.
You can break down the structure of a web page in different ways, but it is, I believe, a best practice to set the page's first heading in the HTML H1 tag and then to use the H2 tag for either the subheading or subsequent sections. If you use H2 for a subheading directly under the H1 tag (as this page does), then H3 might become the heading used for the subsequent sections. The point is that you want to begin with the H1 heading at the top of the page and create a hierarchy from the top down, with each subsequent section that is at the same level in the hierarchy being represented by the same size heading. Each nested subsection is headed by a smaller sized heading. The result is an outline format that might look something like this:
h1 = main page heading h2 = subheading under main heading h3 = section heading h3 = section heading h4 = subsection heading h5 = nested subsection heading
Here's an example from a table of contents that captures the outine structure of a web page:
Interpretative Procedures in Discourse Analysis --------------- Table of Contents 1 Introduction 2 Methodological Issues 2.1 Points of Departure 2.2 Methodological Determinism 3 Pragmatic Interpretations 3.1 Speech Act Theory 3.2 Interactional Sociolinguistics 4 Conclusion 5 Notes 6 Related Pages --------------- 1 Introduction ...
In the text of the web page, each section shown in the table of contents above would have a heading level that indicates its topical depth. So, in the running text of the page (not in the table of contents), the headings would be marked up like this:
<h1>Interpretative Procedures in Discourse Analysis</h1> ... <h2>1 Introduction</h2> <h2>2 Methodological Issues</h2> <h3>2.1 Points of Departure</h3> <h3>2.2 Methodological Determinism</h3> <h2>3 Pragmatic Interpretations</h2> <h3>3.1 Speech Act Theory</h3> <h3>3.2 Interactional Sociolinguistics</h3> <h2>4 Conclusion</h2> <h2>5 Notes</h2> <h2>6 Related Pages</h2>
The sizes of the HTML headings reveals semantic hierarchy to search engines. The h1 heading marks the highest level in the semantic hierarchy. The h2 heading marks the second highest level in the semantic hierarchy. The h3 heading marks the third highest level in the semantic hierarchy, and so forth.
<h1>Most important heading, used only once, at top of page</h1> <h2>Second Most Important Heading Level</h2> <h3>Third Most Important Heading Level</h3> <h4>Fourth Most Important Heading Level</h4>
Using the HTML heading tags to make the structure of your information explicit and reveal the semantic hierarchy of your page's content helps improve your web page's ranking in search engines such as Google. What's more: It helps readers navigate through the content of your web page.
-- Steve Hoenisch
First Published: May 27, 2010. Last Updated: May 27, 2010.