The insertData() method of the CharacterData interface inserts the provided data into this CharacterData node's current data, at the provided offset from the start of the existing data. The provided data is spliced into the existing data.
insertData(offset, data)offsetThe offset number of characters to insert the provided data at. 0 is the first character of the string.
dataThe data to insert.
None.
IndexSizeError DOMExceptionThrown if offset is negative or greater than the length of the contained data.
<span>Result: </span>A string.const span = document.querySelector("span");
const textNode = span.nextSibling;
textNode.insertData(2, "long ");