#IntersectionObserver: relativeTo() method

The relativeTo method can be used to specify a reference node. The reference node is specified by id. The viewport of the reference node can be scaled according to margins.

#grammar

relativeTo(
   selector: string,
   margins ? margins : {left: 0, right: 0, top: 0, bottom: 0}
): IntersectionObserver;

#Parameters

#selector

selector: string;

Specify the id used when searching for the reference node. It will first search in the component passed in when creating the IntersectionObserver object. If not found, the global search will be performed. If the global search is not found, LynxView will be used as the reference node.

#margins

margins ? margins : { left: 0, right: 0, top: 0, bottom: 0 };

Specifies the zoom value of the reference node window. This value only affects the detection of the intersection state and does not affect the actual view display. A positive value means expanding the reference node window boundary, and a negative value means shrinking the reference node window boundary.

#return value

IntersectionObserver object.

#Precautions

The intersection state between the target node and the reference node and the target node and the ancestor node is defined as the smallest intersection ratio as follows:

1. When the reference node is valid, that is, the reference node is the ancestor node of the target node, select the smallest
   • The intersection ratio of the target node and the reference node (scaled by margins)
   • The intersection ratio between the target node and the ancestor node. The ancestor node includes the nodes on the path from the target node to the reference node. The ancestor node will be ignored when overflow: visible is set.
2. When the reference node is invalid, that is, the reference node is not the ancestor node of the target node or there is no node with the id set, select the smallest one below
   • The intersection ratio between the target node and LynxView (scaled by margins)
   • The intersection ratio between the target node and the ancestor node. The ancestor node includes the nodes on the path from the target node to LynxView. The ancestor node will be ignored when overflow: visible is set.

#Compatibility