React has implemented a browser-independent events and DOM system for performance and cross-browser compatibility reasons. We took the opportunity to clean up a few rough edges in browser DOM implementations.

• All DOM properties and attributes (including event handlers) should be camelCased to be consistent with standard JavaScript style. We intentionally break with the spec here since the spec is inconsistent. However, data-* and aria-* attributes conform to the specs and should be lower-cased only.
• The style attribute accepts a JavaScript object with camelCased properties rather than a CSS string. This is consistent with the DOM style JavaScript property, is more efficient, and prevents XSS security holes.
• Since class and for are reserved words in JavaScript, the JSX elements for built-in DOM nodes should use the attribute names className and htmlFor respectively, (eg. <div className="foo" /> ). Custom elements should use class and for directly (eg. <my-tag class="foo" /> ).
• All event objects conform to the W3C spec, and all events (including submit) bubble correctly per the W3C spec. See Event System for more details.
• The onChange event behaves as you would expect it to: whenever a form field is changed this event is fired rather than inconsistently on blur. We intentionally break from existing browser behavior because onChange is a misnomer for its behavior and React relies on this event to react to user input in real time. See Forms for more details.
• Form input attributes such as value and checked, as well as textarea. More here.