jQuery.contains

Requirements

• Implement jqueryContains(container, contained). Return true for an element that is a direct child or deeper descendant of container, and false otherwise.
• Only element nodes are supported. Return false for null, text/comment nodes, or other non-element arguments. Assume inputs are actual DOM nodes or null.
• An element does not count as its own descendant. Siblings, ancestors of container, and unrelated elements return false.
• Detached trees work normally; attachment to document is not required. Use the current parent chain, so moving or removing elements changes the result.
• Do not mutate the DOM or use native contains, compareDocumentPosition, or an external DOM library. Shadow-host traversal is outside scope; follow parentNode only. HTML and CSS fixtures are supplied by tests and are not part of the solution.

Examples

Input: const outer = document.createElement('div');
const inner = document.createElement('span');
outer.appendChild(inner);
jqueryContains(outer, inner);
Output: true

Input: jqueryContains(outer, outer);
Output: false

Input: jqueryContains(inner, outer);
Output: false