HTML4 and HTML5 Key Differences: Compare Side by Side

HTML (Hypertext mark up language) is used for presenting data on WWW (World Wide Web).

HTML is a mark up language used to create structured documents on the internet.

The web is constantly evolving. New and innovative websites are being created every day, pushing the boundaries of HTML in every direction. HTML has been in continuous evolution since it was introduced to the Internet in the early 1990’s.

Other useful HTML tutorials:

HTML4 became a W3C Recommendation in 1997. While it continues to serve as a rough guide to many of the core features of HTML, it does not provide enough information to build implementations that interoperate with each other and more importantly with a critical mass of deployed content.Various versions of this standard have been launched and HTML5 is its latest version.

To give authors more flexibility,enable more interactive and exciting websites and applications, HTML5 introduces and enhances a wide range of features including form controls, APIs, multimedia, structure, and semantics.

HTML4 and HTML5 Main Differences

Now it’s time to take a few steps back and take a look at some of the differences between HTML4 and HTML5.

Mark Up

Some deprecated tags in HTML4 have been removed. These include <font> or <centre>. These functionalities are expected to be achieved using Cascaded Style Sheets (CSS).

HTML5 is developed keeping in mind the usage of modern websites. Tags like <nav> website navigation block and <footer > for bottom lines in web page have been added

Error Handling

HTML4 purposely supports ‘tag soup’, or the ability to write malformed code and have it corrected into a valid document. The problem is that the rules for doing this aren’t written down anywhere. When a new browser vendor wants to enter the market, they just have to test malformed documents in various browsers (especially IE) and reverse-engineer their error handling.

HTML5 is attempting to discover and codify this error handling, so that browser developers can all standardize and greatly reduce the time and money required to display things consistently.

Multimedia Features

In order to play some audio or video file through HTML4 page, third party tool is required such as Adobe flash player.

This is not the case with HTML5. Now multimedia features will be provided inbuilt in the HTML5 specification. This will be done using simple <audio> and <video> tags.


HTML5 introduces a number of APIs that help in creating Web applications. These can be used together with the new elements introduced for applications:

  • API for playing of video and audio which can be used with the new video and audio elements
  • An API that enables offline Web applications
  • An API that allows a Web application to register itself for certain protocols or media types
  • Editing API in combination with a new global contenteditable attribute
  • Drag & drop API in combination with a draggable attribute
  • API that exposes the history and allows pages to add to it to prevent breaking the back button

Browser Support

HTML5 is not yet an official standard, and no browsers have full HTML5 support. But all major browsers (Safari, Chrome, Firefox, Opera, Internet Explorer) continue to add new HTML5 features to their latest versions.

Final Words

There are many other smaller efforts taking place in HTML5, such as better-defined semantic roles for existing elements (<strong> and <em> now actually mean something different, and even <b> and <i> have vague semantics that should work well when parsing legacy documents).

And adding new elements with useful semantics – <article>, <section>, <header>, <aside>, and <nav> should replace the majority of <div>s used on a web page, making your pages a bit more semantic, but more importantly, easier to read.


HTML4 or 5 are nothing but two versions of this standard, HTML5 being the latest.


  • Was developed by World Wide Web consortium and web hypertext application technology working group (WHATWG)
  • Lacks rules for parsing and hence it is difficult to handle errors
  • Contains some deprecated tags such as <font> and <centre> that are removed in next version
  • No multimedia support without third party software


  • Is being developed by WHATWG (web hypertext application technology working group) and W3C HTML WG
  • New tags like <nav> website navigation block and <footer > for bottom lines in web page have been added
  • Strict parsing and lexing rules are introduced to handle any errors
  • It includes multimedia elements (<audio> and <video>)

In Closing

It would be my pleasure to read your comments and please don’t hesitate to add anything as you fully realize that it is necessary for learning.

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