Range.setStartBefore()

The Range.setStartBefore() method sets the start position of a Range relative to another Node. The parent Node of the start of the Range will be the same as that for the referenceNode.

range.setStartBefore(referenceNode);

referenceNode

The Node before which the Range should start.

var range = document.createRange();
var referenceNode = document.getElementsByTagName("div").item(0);

range.setStartBefore(referenceNode);

• The DOM interfaces index