Today most of the browsers use a flash plugin to play the videos. This works pretty well but Flash, unfortunately, requires a lot of computing power. This would be an issue if the system has a low-end configuration Hence the new web standard HTML5 is trying to change that.
HTML5 has been designed with audio and video codecs which take less processing power its equivalent Flash player which rules the browsers audio and video plugin. As with most new technologies, things are not always clearcut.
HTML5 is the largest ever opensource project undertaken by W3C. Hence we can expect some terrific improvements in processing efficiency from HTML5, it should not be assumed that it will completely replace Flash or even have a critical impact, especially on rich web content. Flash still has many advantages such as.

HTML5, the latest version of HTML series offers a number of unique features that will change the way websites and users interact between them.Even though HTML5 has got many features it has got 5 important features which revolutionize the way users view websites and clearly distinguish them from the previous versions. HTML5 will significantly change the way websites are designed.Search engines will get access to tap into a richer source of information.

HTML5 we continue where we left off.

<strong> tag

It is one kind of text formatter used to bold the text.

This is <strong>important</strong>.

<style> tag

The HTML <style> tag is used for declaring style sheets within your HTML document.

<style type="text/css">
 h1 {color:red}
 p {color:blue}
 </style>

<sub> tag

The HTML sub tag is used for subscript text

<p>The HTML sub tag is used for <sub>subscript text</sub></p>.

<summary> tag

The HTML <summary> tag indicates a rundown/subtitle that can be utilized related to the HTML5 <details> tag. This synopsis/inscription can be tapped on to summary/caption  the points of interest as required.

<figure> tag

The HTML <figure> tag is used for annotating illustrations, diagrams, photos, code listings, etc.You can use the <figure> element to associate a caption together with some embedded content, such as a graphic or video.

<form> tag

The <form> tag is used to create an HTML form for user input.The form element contains one or more form elements like: button, input, keygen, object, output, select, textarea and more.
Example

The Doctype

The doctype declaration is not an HTML tag. This  tag is used for specifying the language and version the document is using. The <!DOCTYPE> tag does not have an end tag and it is not case sensitive too.  The HTML5 specification recommends that all documents should have  <!DOCTYPE> header at the top of it.

Example

<!DOCTYPE>
 <html>
 <head>
 <title>Using Doctype</title>
 </head>
 <body>
 <p>Hello world!</p>
 </body>
 </html>

<a> tag

This <a > tag is used to link another page from a webpage. The attribute target in <a> tag can be used to specify if the  new page should open in a  new tab or in a new window.