Node.replaceChild()

The Node.replaceChild() method replaces a child node within the given (parent) node.

Note the idiosyncratic argument order (new before old). ChildNode.replaceWith() may be easier to read and use.

let oldChild = parentNode.replaceChild(newChild, oldChild);

newChild

The new node to replace oldChild. If it already exists in the DOM, it is first removed.

oldChild

The child to be replaced.

The returned value is the replaced node. This is the same node as oldChild.

// Given:
// <div>
//  <span id="childSpan">foo bar</span>
// </div>

// Create an empty element node
// without an ID, any attributes, or any content
var sp1 = document.createElement("span");

// Give it an id attribute called 'newSpan'
sp1.id = "newSpan";

// Create some content for the new element.
var sp1_content = document.createTextNode("new replacement span element.");

// Apply that content to the new element
sp1.appendChild(sp1_content);

// Build a reference to the existing node to be replaced
var sp2 = document.getElementById("childSpan");
var parentDiv = sp2.parentNode;

// Replace existing node sp2 with the new span element sp1
parentDiv.replaceChild(sp1, sp2);

// Result:
// <div>
//   <span id="newSpan">new replacement span element.</span>
// </div>

• Node.removeChild
• ChildNode.replaceWith