帮看下这段 js 代码是干啥的

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function offset(el) {
  let left = 0
  let top = 0

  while (el) {
    left -= el.offsetLeft
    top -= el.offsetTop
    el = el.offsetParent
  }

  return {
    left,
    top,
  }
}

+号求得是 el 到 body 元素的偏移距离

-号是啥玩意.....

2 replies • 2019-12-16 17:51:50 +08:00

imherer

Dec 16, 2019

不都是求和么？只不过一个正一个负

TomVista

Dec 16, 2019

@imherer 我没算初始值 0 ........... :dog