// Selects the first matched DOM element.
let myElem = jQuery('.elemClass:first');
/*
Some notes:
- Because :first is a jQuery extension and not part
of the CSS specification, queries using :first cannot
take advantage of the performance boost provided by the
native DOM querySelectorAll() method. To achieve the
best performance when using :first to select elements,
first select the elements using a pure CSS selector,
then use .filter(":first").
- Selected elements are in the order of their appearance
in the document.
*/