querySelector method
The DocumentFragment.querySelector()
method returns the
first element, or null
if no matches are found, within the
DocumentFragment (using depth-first pre-order traversal of the
document's nodes) that matches the specified group of selectors.
If the selector matches an ID and this ID is erroneously used several times in the document, it returns the first matching element.
If the selectors specified in parameter are invalid a DOMException with
a SYNTAX_ERR
value is raised.
Implementation
external Element? querySelector(String selectors);