The comparePoint() method of the Range interface determines whether a specified point is before, within, or after the Range. The point is specified by a reference node and an offset within that node.
comparePoint(referenceNode, offset)referenceNodeThe Node that the offset is relative to.
offsetAn integer greater than or equal to zero describing the position inside referenceNode of the point to be checked. If referenceNode is a Node of type Text, Comment, or CDATASection, then offset is the number of characters from the start of referenceNode. For other Node types, offset is the number of child nodes from the start of the referenceNode.
A number.
-1 if the point specified by the referenceNode and offset is before the start of this Range.0 if the point specified by the referenceNode and offset is within this Range (including the start and end points of the range).1 if the point specified by the referenceNode and offset is after the end of this Range.const text = new Text("0123456789");
const thisRange = new Range();
thisRange.setStart(text, 1);
thisRange.setEnd(text, 6);
thisRange.comparePoint(text, 3); // 0
thisRange.comparePoint(text, 0); // -1
thisRange.comparePoint(text, 6); // 0
thisRange.comparePoint(text, 7); // 1