React manually stringifies all attributes before assigning them: https://github.com/facebook/react/blob/master/packages/react-dom/src/client/DOMPropertyOperations.js#L169-L179 This appears to be for IE8/9. However it's possible that this is an IE8 only behavior. See IE9: <img width="1104" alt="screen shot 2017-11-30 at 8 02 51 pm" src="https://user-images.githubusercontent.com/590904/33463221-2eeb4770-d60a-11e7-9915-2a2918ca22b9.png"> <img width="752" alt="screen shot 2017-11-30 at 8 03 38 pm" src="https://user-images.githubusercontent.com/590904/33463224-3595328e-d60a-11e7-9786-e2ac050ffb53.png"> Can we get rid of `'' + value` in DOMPropertyOperations?