Function testContext

notes/docsify/unpkg/gotop/jquery-2.1.0.js:984–986

* Checks a node for validity as a Sizzle context * @param {Element|Object=} context * @returns {Element|Object|Boolean} The input node if acceptable, otherwise a falsy value

( context )

 * @returns {Element|Object|Boolean} The input node if acceptable, otherwise a falsy value
 */
function testContext( context ) {
	return context && typeof context.getElementsByTagName !== strundefined && context;
}

// Expose support vars for convenience
support = Sizzle.support = {};