.offsetParent()

Categories: Offset | Traversing > Tree Traversal Chinese Translation: .offsetParent()

.offsetParent()Returns: jQuery

Description: Get the closest ancestor element that is positioned.

Given a jQuery object that represents a set of DOM elements, the .offsetParent() method allows us to search through the ancestors of these elements in the DOM tree and construct a new jQuery object wrapped around the closest positioned ancestor. An element is said to be positioned if it has a CSS position attribute of relative, absolute, or fixed. This information is useful for calculating offsets for performing animations and placing objects on the page.

Consider a page with a basic nested list on it, with a positioned element:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
 
<ul class="level-1">
  <li class="item-i">I</li>
  <li class="item-ii" style="position: relative;">II
    <ul class="level-2">
      <li class="item-a">A</li>
      <li class="item-b">B
        <ul class="level-3">
          <li class="item-1">1</li>
          <li class="item-2">2</li>
          <li class="item-3">3</li>
        </ul>
      </li>
      <li class="item-c">C</li>
    </ul>
  </li>
  <li class="item-iii">III</li>
</ul>

If we begin at item A, we can find its positioned ancestor:

1
 
$( "li.item-a" ).offsetParent().css( "background-color", "red" );

This will change the color of list item II, which is positioned.

Example:

Find the offsetParent of item "A."

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
 
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>offsetParent demo</title>
  <script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
 
<ul class="level-1">
  <li class="item-i">I</li>
  <li class="item-ii" style="position: relative;">II
    <ul class="level-2">
      <li class="item-a">A</li>
      <li class="item-b">B
        <ul class="level-3">
          <li class="item-1">1</li>
          <li class="item-2">2</li>
          <li class="item-3">3</li>
        </ul>
      </li>
      <li class="item-c">C</li>
    </ul>
  </li>
  <li class="item-iii">III</li>
</ul>
 
<script>$( "li.item-a" ).offsetParent().css( "background-color", "red" );</script>
 
</body>
</html>

Demo: