The HTMLElement.offsetParent read-only property returns a reference to the element which is the closest (nearest in the containment hierarchy) positioned ancestor element.
A positioned ancestor might be:
td, th, table in case the element itself is static positioned.If there is no positioned ancestor element, the body is returned.
Note: offsetParent returns null in the following situations:
display property set to none.position property set to fixed and its containing block is the viewport. If the containing block is not the viewport, offsetParent returns the nearest ancestor that forms a containing block, for example, an ancestor with transform, perspective, or filter styles set.<body> or <html>.offsetParent is useful because offsetTop and offsetLeft are relative to its padding edge.
An object reference to the element in which the current element is offset.