Why Does an Absolutely Positioned Element Within a Relatively Positioned Element Inherit Its Position from Its Immediate Parent?

Absolute Positioning Within Relative Positioning: Why the Hierarchy Matters

In HTML, the positioning of elements is determined by the CSS positioning property. When an element is assigned absolute positioning, it is removed from its normal flow in the document, and its position is instead defined relative to its closest ancestor with position: absolute or position: relative.

Question:

Consider the following HTML structure:

<div id="1st">
  <div id="2nd">
    <div id="3rd"></div>
  </div>
</div>

If the first div has position: relative, the second div has position: absolute, and the third div also has position: absolute, why is the third div positioned absolutely relative to the second div and not the first div?

Answer:

The key to understanding this behavior lies in the way absolute positioning affects the position of child elements.

When an element is absolutely positioned, any child elements it contains are also positioned absolutely relative to it, even if those child elements have their own absolute positioning. This is because absolute positioning effectively resets the default relative positioning for child elements.

In our example, the third div is positioned absolutely relative to the second div because the second div has position: absolute. The absolute positioning of the first div (with position: relative) has no effect on the positioning of the third div because it is not a direct ancestor of the third div.

To achieve the desired behavior of having the third div positioned absolutely relative to the first div, we would need to remove the absolute positioning from the second div and make the third div a direct child of the first div:

<div id="1st">
  <div id="3rd"></div>
</div>

The above is the detailed content of Why Does an Absolutely Positioned Element Within a Relatively Positioned Element Inherit Its Position from Its Immediate Parent?. For more information, please follow other related articles on the PHP Chinese website!