10. Things missing in IE9
Video codecs CSS3 Transitions (not transforms)
File API CSS3 Text Shadow
HTML5 History API CSS3 Gradients
Drag'n Drop from Desktop CSS3 Border Image
CSS3 Flex box model
Application Cache (offline)
Web Workers (threads in JavaScript) JavaScript Strict Mode
HTML5 Forms (validation mechanism, ForeignObject (embed external content in
CSS3 selectors) SVG)
SMIL Animations (SVG animations)
Web Sockets
WebGL (3D) ClassList APIs
FormData