It’s platform-agnostic, perfect for simultaneous Web and mobile coding, and soon to be the new Web standard. It’s also the key to giving businesses a much-needed mobile presence.

The “it” is HTML5. This year, businesses like Facebook (News – Alert) saw mobile users surpass all other users of its website. However, according to stats released by Vizibility earlier this year, only 29 of the top 100 U.S. firms currently have a mobile-friendly website.

HTML5 makes the mobile transition simple by allowing developers to write code one time and then simultaneously apply it to both Web and mobile sites. HTML5 also allows companies to add more features to their mobile websites so that mobile websites and native applications are more difficult to tell apart.

Matt Sottile, a recruiter for Jobspring Boston, recently wrote a blog about how developers and Web designers can rev up their resumes by adding HTML5 as a qualification.

“Currently, most companies don’t require HTML5 as a ‘must-have,’” Sottile wrote, “but I’ve yet to talk to an employer who doesn’t view it as a huge plus.”

No standard is perfect. HTML5 has some vulnerability concerning data, and it doesn’t support the execution of low priority programs, while higher priority programs aren’t using the processing system.

But its fast-loading multimedia support is rendering Flash obsolete, and it allows for freer website design with CSS (News – Alert) and JavaScript. In essence, developers can create more complex applications while requiring less work from the device that’s running them.

Many analysts expect HTML5 to be the Web and mobile standard by 2015. In a sense, HTML added to CSS and mixed with JavaScript APIs has yielded the beauty that is HTML5.

Once HTML5 is the standard, companies will no longer have to produce native applications that require users to process constant downloads. Instead, mobile websites will contain app functionality with real-time updating.

Designers who don’t know HTML5 will find themselves becoming obsolete as mobile gains importance. More and more companies will expect developers to have the language in their arsenal.