Because it matches the field name for DOM nodes: https://developer.mozilla.org/en-US/docs/Web/API/Element/className https://developer.mozilla.org/en-US/docs/We

Because it matches the field name for DOM nodes: https://developer.mozilla.org/en-US/docs/Web/API/Element/className https://developer.mozilla.org/en-US/docs/Web/API/Element/cla...