如何通过选中的文本获取关闭的父div属性？

function getClosedParentDivAttributeFromSelectedText() {
  var selectedText = window.getSelection().toString();
  if (selectedText.length > 0) {
    var range = window.getSelection().getRangeAt(0);
    var ancestorElement = range.commonAncestorContainer;
    while (ancestorElement && ancestorElement.tagName !== 'DIV') {
      ancestorElement = ancestorElement.parentNode;
    }
    if (ancestorElement && ancestorElement.tagName === 'DIV') {
      return ancestorElement.getAttribute('属性名');
    }
  }
  return null;
}