HTML DOM contains() Method

contains()Returns a boolean value indicating whether the node passed in is a child node of the current node.

Syntax:

node.contains(node)

Example

var p = document.getElementById("myP");
var div = document.getElementById("myDIV");
div.contains(p);

All browsers fully support the contains() method:

Method
contains()	Yes	Yes	Yes	Yes	Yes

Parameter	Description
node	Specify the node (and its descendants) that may contain the specified node

Return value:	A boolean value indicating whether the node is a child of the given node. Possible values: true-The node is a descendant false-The node is not a child node