I'm trying to embed HTML5/createJS in a SP Content Editor Web Part.
On my browser (Chrome):
In SharePoint (Chrome): The background CSS renders, but not the createJS/HTML5 elements (canvas):
You have to change the browser mode in the masterpage, by default SP2010 forces the browser mode to IE8, you can change it to EDGE, but this way you will lose some default features like the rich text editor in the multiple line text boxes.
<meta http-equiv="X-UA-Compatible" content="IE=8"/>
<meta http-equiv="X-UA-Compatible" content="IE=EDGE"/>
You can get it to work by modifying the masterpage, but things break and its probably not a good idea. However, having said that, there have been a few instances i have seen where guys are trying to get it to work
Have a look here for example. There is also a lot more out on the web.
SharePoint 2010 does not support HTML 5 or CSS 3.