javascript - Element.getClientRects() 何时返回多个对象的集合？

Question

每次我调用 Element.getClientRects() 时，它都会返回一个仅包含一个 DOMRect 对象的集合。

Element.getClientRects() 何时返回多个 DOMRect 对象的集合？

function handleClick() {
  console.log(event.target.getClientRects())
}

<ul 
  style="border: 1px solid black;" 
  onclick="handleClick()"
>
    <li>Click the text to see in console</li>
</ul>

Answer 1

The return value of Element.getClientRects() method is a collection of DOMRect objects, each associated with one CSS border-box around an element.

当元素有多个 border-boxes(如内联元素)时，Element.getClientRects() 返回多个 DOMRect 对象。一个例子:

let p = document.querySelector('p');
let span = document.querySelector('span');

console.log(p.getClientRects().length);
console.log(span.getClientRects().length);

p {
  border: 1px solid green;
}
span {
  border: 1px solid red;
}

<p>
  This is a paragraph with
  <span>Span Element having a looooooooooooooooooooooo nnnnnnnnnnnnnnnnnnnn ggggggggggggggggg text</span>
</p>

此外，返回值取决于屏幕分辨率。尺寸越小，CSS border-boxes 的数量就越少。