Node: isConnected property
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.
The read-only isConnected property of the Node interface returns a boolean indicating whether the node is connected (directly or indirectly) to a Document object.
Value
A boolean value that is true if the node is connected to its relevant context object, and false if not.
Note:
An Attr node always returns false for isConnected, even when its ownerElement is connected.
This is because, even though an attribute is associated with an element via ownerElement, it is not part of the node tree — it has no parent node, and it is its own root node.
Since isConnected is only true when a node's root is a document, an Attr node is never considered connected.
Examples
Standard DOM
A standard DOM example:
let test = document.createElement("p");
console.log(test.isConnected); // Returns false
document.body.appendChild(test);
console.log(test.isConnected); // Returns true
Shadow DOM
A shadow DOM example:
// Create a shadow root
const shadow = this.attachShadow({ mode: "open" });
// Create some CSS to apply to the shadow DOM
const style = document.createElement("style");
console.log(style.isConnected); // returns false
style.textContent = `
.wrapper {
position: relative;
}
.info {
font-size: 0.8rem;
width: 200px;
display: inline-block;
border: 1px solid black;
padding: 10px;
background: white;
border-radius: 10px;
opacity: 0;
transition: 0.6s all;
positions: absolute;
bottom: 20px;
left: 10px;
z-index: 3
}
`;
// Attach the created style element to the shadow DOM
shadow.appendChild(style);
console.log(style.isConnected); // Returns true
Specifications
| Specification |
|---|
| DOM # ref-for-dom-node-isconnected① |