HTML5 is a markup language for structuring and presenting content for the World Wide Web, and is a core technology of the internet originally proposed by Opera Software.
HTML5 introduces a number of new elements and attributes that reflect typical usage on modern websites. Some of them are semantic replacements for common uses of generic block and inline elements. Some deprecated elements from HTML 4.01 have been dropped, including purely presentational elements, whose effects are achieved using Cascading Style Sheets (CSS). There is also a renewed emphasis on the importance of DOM scripting (JavaScript) in web behavior.
The HTML5 syntax is no longer based on SGML (Standard Generalized Markup Language) despite the similarity of its markup. It has, however, been designed to be backward compatible with common parsing of older versions of HTML. It comes with a new introductory line that looks like an SGML document type declaration, which triggers the standards-compliant rendering mode. As of 5 January 2009, HTML5 also includes Web Forms 2.0, a previously separate WHATWG (Web Hypertext Application Technology Working Group) specification.
Basically HTML5 has many new syntactical features, as well as the integration of SVG content. Due to these new elements, it will be very easy to integrate multimedia and graphical content to web without using flash and third party plugins. There are also another new elements which enrich the semantic value of the document. Other major advantages, as well as some disadvantages of HTML5 are described below.
Advantages
Mutuality
Due to usability purpose the web sites made by developers are highly interactive nowadays and for this developers need to include fluid animations, stream video, play music and social network sites like Facebook and Twitter into the websites. Until now, they have only the option to integrate it with the help of Flash or Silverlight, Flex or JavaScript like tools. But these consume so much time to develop and even the complexity of web application also increased. But now with the help of HTML5 it is possible to embed video and audio, high quality drawings, charts and animation and many other rich content without using any plugins and third party software the functionality is built into the browser.
Improved Code
HTML 5 will enable web designers to use cleaner, neater code, we can remove most div tags and replace them with semantic HTML 5 elements.
In HTML5, feedback job areas will be much simpler to create, and much simpler to use, and send information more properly. For example, in the current present HTML world, when an feedback area needs to be considered as "required," a program is necessary to establish the type and check out that a customer has packed in that particular area.
Improved Semantics
Now it is easy to see which parts of the page are headers, nav, footers, aside, etc as the tags are specific for these all and most importantly know what their meaning and purpose is in whole the format. By using HTML5 elements we can increase the semantic value of the web page as the codes are very standardized.
There are a lot of factors why HTML5 will modify the way your web page operates. It's also worth noting that it might be a chance to start changing your web page to present styles and expectations, as the world wide web is about to create a very big switch under the cover.
Elegant Forms
HTML5 enables designer to use more fancier forms. Even it makes form validation native to HTML, User interface enhancements and reduced need for JavaScript (only needed in browsers that don’t support form types). There will be different type of text inputs, search and different fields for different purpose.
Consistency
As websites adopt the new HTML5 elements we will see more greater consistency in terms of the HTML used to code a web page on one site compared to another. This will make it more easier for designers and developers to immediately understand how a web page is structured.
Programming practices vary so greatly among different coding languages, that some developers would rather just stick with what they know than struggle trying to adapt to something new. Developers will be happy to know that from a structural standpoint, nothing has changed with HTML5. The same fundamentals still apply. This means that if you or your developer are familiar with version 4.01, the current standard, you will be able to thrive with the fifth revision.
Improved Accessibility
Different technologies can elaborate on the features with the help of HTML5, as they can Immediately make more detailed understanding of the structure of a page by take a look at HTML5 elements it has.
Fulfill Web application Needs
Many new features and standards have emerged as part of HTML 5. Once you detect the available features in today’s browsers, you can take advantage of those features in your application. Main focus of HTML5 is to make easier application with easy front-ends, drag and drop tools, discussion boards, wikis and other useful elements.
Offline Application Cache
All browsers have some kind of caching after a sometime. HTML 5 provides a smarter solution. While building the site, the developer can specify the files that the browser should cache. For example. if you refresh a web page when you are offline, the page will still load correctly. This sort of caching has several advantages like offline browsing, files load much faster and reduced load on server.
Client-Side Database
While cookies have been used to track unique user data for years, they have serious disadvantages. The largest flaw is that all of your cookie data is added to every HTTP request header. This can end up having a measurable impact on response time. So a best practice is to reduce cookie size. With HTML5 we can do better by using sessionStorage and localStorage (storage in HTML5) in place of cookies. It is not a permanent database, but enables you to temporarily store structured data.
Geolocation Support
With help of Geolocation anyone can find out where you are in the world. There is different ways to figure out where you are: IP address, wireless network connection, cell tower, or dedicated GPS hardware that calculates latitude and longitude from information sent by satellites in the sky. But The new HTML5 geolocation APIs make location, whether generated via GPS or other methods, directly available to any HTML5-compatible browser-based application.
Better Media Handling
HTML is known for its flexibility, but one of its biggest flaws has been the inability to efficiently handle multimedia content. For example, in order to play a flash video, a user must install a plugin such as Adobe Flash, which requires the use of various other elements to function in harmony with the user’s browser. HTML5 is equipped with built-in elements that enable it to handle multimedia content efficiently. This simply means that you can incorporate video, audio, and other rich media content with relative ease, while your visitors can enjoy it without installing a browser extension.
Cross-Browser Compatibility
When it comes to HTML5, one of the most important factors a business must take into consideration is browser support. Will it be compatible with the browsers your visitors are using to view your website? The good thing is that all the popular web browsers are being designed with HTML5 in mind. In fact, Windows Internet Explorer, Mozilla Firefox, and Google Chrome have all been updated with features that support the newest version of the standard. Apple and Google have even optimized their browsers to accommodate the mobile users of iPhone and Android platforms respectively.
Disadvantages
Browser Support
The main problem with HTML5's acceptance is that only modern browsers support it. There are things you can do to make the language play nice with older browsers, but none of them are perfect.
Language in Progress
Another problem is that although parts of the language are very stable, the language itself is considered a work in progress, so technically, any of the elements could change at any time. The language is not expected to be completed for several years, which complicates things further.
Media Licensing
Because of the media licensing issue, you will have to use different formats for running rich media applications. But this issue is expected to get resolved soon. Until it is resolved, you will have to go through more work.
No URI or DOCTYPE
DOCTYPE (Document Type Declaration) was introduced to display the web pages properly even if the browser was having a hard time understanding a few elements of the coding. HTML5 also does not have any URI (Uniform Resource Identifier) which means that it will not work with the browsers that are not compatible with HTML5.
Retaining Old Elements
HTML5 retains a few old elements.
Conclusion
There are a lot of factors why HTML5 will modify the way your web page operates. It is also worth noting that it might be a chance to start changing your web page to present styles and expectations, as the World Wide Web is about to create a very big switch under the cover.