code: function ariaTextboxValue(virtualNode) {
  	const { actualNode } = virtualNode;
  	const role = aria.getRole(actualNode);
  	if (role !== 'textbox') {
  		return '';
  	}
  	if (!dom.isHiddenWithCSS(actualNode)) {
  		return text.visibleVirtual(virtualNode, true);
  	} else {
  		return actualNode.textContent;
  	}
  }
docs: Calculate value of a an element with role=textbox
  
  @param {VirtualNode} element The VirtualNode instance whose value we want
  @return {string} The calculated value