Text：assignedSlot 属性
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.
Text 接口的 assignedSlot 只读属性返回与元素相关联的 HTMLSlotElement 对象。
值
HTMLSlotElement，如果文本节点没有关联 <slot> 元素，则为 null。
规范
| Specification |
|---|
| DOM # dom-slotable-assignedslot |