function getNodeForCharacterOffset(root, offset) {
	  var node = getLeafNode(root);
	  var nodeStart = 0;
	  var nodeEnd = 0;

	  while (node) {
	    if (node.nodeType === 3) {
	      nodeEnd = nodeStart + node.textContent.length;

	      if (nodeStart <= offset && nodeEnd >= offset) {
	        return {
	          node: node,
	          offset: offset - nodeStart
	        };
	      }

	      nodeStart = nodeEnd;
	    }

	    node = getLeafNode(getSiblingNode(node));
	  }
	}
Get object describing the nodes which contain characters at offset.

@param {DOMElement|DOMTextNode} root
@param {number} offset
@return {?object}