HTML5 is the future trend in the world of web application development no matter it is phone or desktop. Its still under the development and expected to be release by the end of year 2014. Seeing the future, almost all browser vendors have been come with expected features of HTML5.
I strongly recommend having a go through with HTML5 with CSS3 to be in race of development. It’s interesting to see that many un-noticed previous HTML tags have been eliminated and new tags have been introduced into HTML5.
Along with browser vendors, others have also taken this new technique onto top and have started making their products with HTML5 compliance or with help of HTML5. No one want to be behind and giving their hands into HTML5 and CSS3 based development, so why you?