isConnected?The read-only isConnected property returns a boolean: true if the node is connected (directly or indirectly) to a Document, otherwise false (MDN).
Status: Baseline Widely available (since January 2020) — not Deprecated, Experimental, or Non-standard. Note: an Attr node always returns false, even when its ownerElement is connected.
node.isConnected
→ true // in a Document (or connected shadow tree)
→ false // created but not inserted, or removed
MDN flow:
el = document.createElement("p") → false
document.body.appendChild(el) → true| Situation | Typical value |
|---|---|
| In the page / connected shadow | true |
| Just created / removed / in a fragment only | false |
Attr node | Always false |
isConnectedRead the flag before you assume a node is still in the document.
node.isConnected.true, the node is in a document tree (or connected shadow).false, insert it first — or skip DOM work that needs a live node.| Piece | Required? | Role |
|---|---|---|
node | Yes | Any Node to check |
| Return | — | boolean |
| Writable? | No | Read-only |
el = document.createElement("p")
print el.isConnected // false
document.body.appendChild(el)
print el.isConnected // true
el.remove()
print el.isConnected // false
// Attr caveat (MDN):
attr.isConnected // always falseQuick facts for connected vs detached nodes.
| Topic | Detail |
|---|---|
| Returns | true / false |
| Meaning | Connected to a Document? |
| After create | false until inserted |
| Shadow DOM | true if host is connected |
Attr | Always false |
| Standard | Baseline Widely available (since Jan 2020) |
Create a node, append it, then remove it — watch isConnected flip.
Short, copy-ready snippets. Open DevTools Console, or use Try It Yourself for a live editor.
MDN standard DOM: false after create, true after append.
const test = document.createElement("p");
console.log(test.isConnected); // false
document.body.appendChild(test);
console.log(test.isConnected); // trueDetaching a node flips the flag back to false.
const el = document.createElement("div");
document.body.appendChild(el);
console.log(el.isConnected); // true
el.remove();
console.log(el.isConnected); // falseMDN: a node in a connected shadow root reports true.
const host = document.createElement("div");
document.body.appendChild(host);
const shadow = host.attachShadow({ mode: "open" });
const style = document.createElement("style");
console.log(style.isConnected); // false
shadow.appendChild(style);
console.log(style.isConnected); // trueMDN note: attribute nodes never report connected, even on a live element.
const el = document.createElement("a");
el.setAttribute("href", "/docs");
document.body.appendChild(el);
const attr = el.getAttributeNode("href");
console.log(el.isConnected); // true
console.log(attr.isConnected); // falseel.isConnected is true.ownerElement.Children inside a fragment alone are not connected until inserted.
const frag = document.createDocumentFragment();
const item = document.createElement("li");
frag.appendChild(item);
console.log(item.isConnected); // false
document.body.appendChild(frag);
console.log(item.isConnected); // trueCheck these before treating isConnected as “has a parent.”
MDN: attribute nodes are never considered connected, even on a live element.
Nodes living only in a DocumentFragment stay false until inserted into a document.
parentNode can exist on detached trees; isConnected asks specifically about a Document root.
If the host is in the document, nodes inside its shadow root report true.
Node.isConnected is marked Baseline Widely available on MDN (since January 2020).
Boolean: true if the node is connected to a Document (including connected shadow trees). Attr nodes always return false.
Bottom line: Safe everyday DOM API. Use it to guard work that needs a live document node. See the MDN isConnected reference.
| Approach | Cost | Best for |
|---|---|---|
isConnected | O(1) | Document-connection check |
document.contains(node) | O(1)–O(depth) | Same idea for most elements |
parentNode !== null | O(1) | Has a parent — not Document proof |
Prefer isConnected when the question is “in a document?” — it is clear, cheap, and matches the DOM definition.
true.false (MDN).One line: isConnected answers “is this node in a Document tree?” — not “does it have a parent?”
Learn how to read the last child node of a parent.
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