There’s little doubt that the web seems to be moving inexorably away from technologies such as Flash, Silverlight and Java, toward a world where HTML 5 is king for building interactive web sites with animations, streaming video and other complex web applications. Much has been written about the advantages of HTML 5 in this respect:
http://www.html5arena.com/blog/html5/10-major-advantages-of-html5/
And it’s bound to be a good thing for security, right? We’ve suffered through the almost constant updates to Flash and Java due to the discovery of one security flaw after another. Well, the bad news is that HTML 5 has its own vulnerabilities, including familiar faces such as cross-scripting, stealth attacks, geolocation exploits and more. At last summer’s BlackHat conference, there was a good session on this, and you can read a summary of the 10 ten security threats associated with HTML 5 here:
http://www.securityweek.com/top-10-security-threats-html5-black-hat