HOW TO compare HTML5 features supported by versions 8, 9 & 10 of IE

This page on the Browserscope website lets you choose versions of the same or different browsers & see how they stack up in supporting HTML5 features. Click on the "Compare UAs" link on that page, select User Agents you want to compare & then hit the Compare button.

I chose versions 8, 9 & 10 of Internet Explorer to see what's new with respect to HTML5 in IE9 & IE 10

click to enlarge image

You can copy the table data to Excel & transpose the columns to rows to view the tabular data vertically as a list (in Excel2010, click on Paste dropdown in Ribbon & select Transpose).

So here is the list of HTML5 supported features in IE9 as detected by Browserscope by utilizing Modernizer 2.0.4 -

1. audio:m4a 
2. audio:mp3 
3. backgroundsize 
4. borderradius 
5. boxshadow 
6. canvas 
7. canvastext 
8. csstransforms 
9. draganddrop 
10. fontface 
11. generatedcontent 
12. geolocation 
13. hashchange 
14. hsla 
15. inlinesvg 
16. localstorage 
17. multiplebgs 
18. opacity 
19. postmessage 
20. rgba 
21. sessionstorage 
22. smil 
23. svg 
24. svgclippaths 
25. video:h264 

 IE10 additionally supports the following HTML5 features -

1. applicationcache 
2. cssanimations 
3. csscolumns 
4. cssgradients 
5. csstransforms3d 
6. csstransitions 
7. history 
8. indexeddb 
9. input:autofocus 
10. input:list 
11. input:max 
12. input:min 
13. input:multiple 
14. input:pattern 
15. input:placeholder 
16. input:required 
17. input:step 
18. inputtypes:email 
19. inputtypes:number 
20. inputtypes:range 
21. inputtypes:search 
22. inputtypes:tel 
23. inputtypes:url 
24. textshadow 
25. websockets 
26. webworkers 

Also see:
Comparison of layout engines (HTML5)
HTML5 compatibility across major mobile and tablet browsers