On January 28, 2021, the World Wide Web Consortium (W3C) discontinued the HTML5 standard, switching to the HTML Living Standard, which is developed by the WHATWG (Web Hypertext Application Technology Working Group).

In this article, we introduce the differences between HTML5 and the HTML Living Standard and their relationship with SEO.

The HTML Living Standard represents the ongoing evolution of HTML specifications. Created by development teams from Apple, Opera, and Mozilla under the WHATWG, it has now become the standard for HTML. Unlike previous HTML standards like HTML 1.0 or HTML 5.2, which had version numbers, the HTML Living Standard is continuously updated without such concepts.

Previously, W3C, a well-known international organization that decides the standard specifications for the World Wide Web, created HTML5 and other versions. However, dissatisfied with W3C’s approach of pursuing ideals without considering practical feedback, developers from Apple, Opera, and Mozilla established the WHATWG.

For a period, there were two separate HTML specifications, but now the HTML Living Standard set by WHATWG has become the agreed standard.

The shift to the HTML Living Standard on January 28, 2021, signifies the handover of HTML standard-setting from W3C to WHATWG. Understanding this change requires knowledge of the history of HTML5 discontinuation, the process of HTML specification revisions, and the history of WHATWG.

HTML5 referred to the fifth revision of HTML. The development and transitions of HTML standards over time include

• HTML 1.0 was released as an Internet Draft by the IIIR Working Group of the Internet Engineering Task Force in 1993, created by Tim Berners-Lee.
• HTML 2.0 was officially announced by the same committee in 1995, also by Tim Berners-Lee, adding various elements to the foundation laid by HTML 1.0.
• The attempt to set HTML 3.0 standards by the committee failed amid the browser wars, leading W3C, founded by Tim Berners-Lee, to announce and publish HTML 3.2 standards in 1997, transitioning the responsibility of HTML standard setting to W3C.
• W3C announced HTML 4.0 and 4.01 in rapid succession in 1997 and 1999.
• W3C initiated a major overhaul planning to remove elements determining appearance from HTML, aligning with SGML and moving towards XHTML as the new standard.
• Discontent with these developments, developers from Apple, Mozilla, and Opera founded WHATWG in 2004, setting their own standards.
• After initially cooperating, divergences in approach led to a split between W3C and WHATWG, with WHATWG starting the HTML Living Standard in 2011.
• Both entities aimed to unify standards by 2019, leading to the current agreement where WHATWG’s HTML Living Standard is recognized as the standard.

This history outlines the evolution and the consolidation of HTML standards under the HTML Living Standard by WHATWG, resolving the previously divided specifications.

With a history leading up to it, in 2021, W3C’s HTML standards were phased out in favor of the HTML Living Standard set by WHATWG.

The HTML Living Standard and HTML5 Differences 

To put it simply, the HTML Living Standard and HTML5 are almost identical.

Since the transition from the final version of HTML5, HTML5.2, to the HTML Living Standard, there have been additions, changes, and removals of elements and attributes. However, the major difference lies primarily in the handling of some tags rather than in substantial alterations.

The following details explain these changes more comprehensively. It’s important to note that the HTML Living Standard is constantly updated, necessitating periodic reviews.

Additions in the HTML Living Standard

• <main> for representing the main content of a document.
• <slot> for representing a placeholder within a web component.
• <hgroup> for grouping a set of headings.

Changes in the HTML Living Standard

• The <meta> element can now be placed under certain conditions within the body.
• The <style> element can no longer be placed within the body.
• The <link> element can now be placed under certain conditions within the body.
• The use of the <cite> element has been altered to no longer include the author’s name.

Removals in the HTML Living Standard

• The <rtc> element, previously used for defining a ruby text container for ruby annotation, is removed.
• The <rb> element, used for marking the base text component of ruby annotation, is removed.

Newly Added Attributes in the HTML Living Standard

• onmessageerror=”” for the <body> element to execute a script when an unreadable message is received.
• ping=”” for the <a> and <area> elements to specify destinations for ping requests.
• rel=”” for the <form> element to define the relationship of the linked document to the current one.
• allow=”” for the <iframe> to specify permitted browser features.
• Various attributes for the <link> and <img> elements to enhance link and image functionalities.
• The integrity=”” attribute for the <script> element to verify the integrity of external scripts.
• The nomodule=”” attribute for the <script> to disable script execution in environments that support module scripts.

Attributes Changed in the HTML Living Standard

• The rel=”” attribute now accepts “opener” as a value for the <a>, <area>, and <link> elements.
• The sandbox=”” attribute for the <iframe> element now allows several new values to enhance security.
• The <meta> element’s name=”” and http-equiv=”” attributes now support “theme-color”, “color-scheme”, and other values to specify document-level metadata.

This overview encapsulates the evolution from HTML5 to the HTML Living Standard, highlighting the continuous development and the aim for more dynamic, flexible, and user-friendly web standards.

With a history leading up to 2021, W3C’s HTML standards were discontinued, and HTML was unified under the HTML Living Standard set by WHATWG.

Differences Between HTML Living Standard and HTML5 

To put it simply, the HTML Living Standard and HTML5 are almost identical.

Since the final version of HTML5, HTML5.2, there have been additions, changes, and deletions of elements and attributes with the transition to the HTML Living Standard.

However, the changes are mainly in the handling of some tags, and there are no significant differences.

The HTML Living Standard is continuously updated, so it’s necessary to check the latest information periodically.

Additions in the HTML Living Standard

• The <main> element signifies the primary content of a document.
• The <slot> element represents a slot.
• The <hgroup> element groups a set of headings.

Changes in the HTML Living Standard

• The <meta> element has conditions for placement inside the body element that have changed.
• The <style> element can no longer be placed inside the body element.
• The <link> element has conditions for placement inside the body element that have changed.
• The <cite> element no longer includes the author’s name.

Elements Discontinued in the HTML Living Standard:

• The <rtc> and <rb> elements, which were menu items, have been discontinued.

Attributes Added in the HTML Living Standard:

• The <body> element now includes onmessageerror=”” to execute a script when an unreadable message is received.
• The <a> and <area> elements now include ping=”” to specify ping destinations.
• The <form> element now includes rel=”” to describe the relationship between the current document and the link destination.
• The <iframe> element now includes allow=”” to specify usable browser features.
• The <link> element now specifies color=”” for Safari pin icon color and includes several other new attributes for various purposes.

Attributes Changed in the HTML Living Standard

• The rel=”” attribute for <a>, <area>, and <link> elements now can specify “opener” among other values.
• The sandbox=”” attribute for the <iframe> element now can specify new values for finer control over sandbox behaviors.
• The <meta> element now can specify “theme-color” and “color-scheme” among others.

Web Browsers Supporting the HTML Living Standard 

Main web browsers like Chrome, Firefox, Safari, and Opera now support the HTML Living Standard. Google and Apple’s browsers adopted this standard after the HTML5.1 recommendation in 2016. Microsoft’s Edge also moved to a Chromium base in 2018, aligning with the standard.

SEO Implications of Aligning with the HTML Living Standard 

Markup is crucial for SEO. Improper markup under the HTML Living Standard could negatively impact SEO, whereas appropriate markup can ensure content quality. Utilizing the elements and attributes defined in the HTML Living Standard for markup and eliminating mistakes in HTML element and attribute descriptions are essential. This leads to an HTML structure that is easier for crawlers to understand and reduces layout issues, thereby maintaining content quality and potentially preventing a drop in search rankings.

Summary

the HTML Living Standard, established by WHATWG, represents the current and continuously evolving standard for HTML. Major web browsers have adopted this standard, and although there are minor differences from HTML5, understanding the basics of the HTML Living Standard is recommended to avoid SEO issues.