first selectorversion deprecated: 3.4

Description: Selects the first matched DOM element.

version added: 1.0jQuery( ":first" )

As of jQuery 3.4, the :first pseudo-class is deprecated. Remove it from your selectors and filter the results later using .first().

The :first pseudo-class is equivalent to :eq( 0 ). It could also be written as :lt( 1 ). While this matches only a single element, :first-child can match more than one: One for each parent.

Additional 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.

Example:

Finds the first table row.

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>first demo</title>
  <style>
  td {
    color: blue;
    font-weight: bold;
  }
  </style>
  <script src="https://code.jquery.com/jquery-4.0.0.js"></script>
</head>
<body>
<table>
  <tr><td>Row 1</td></tr>
  <tr><td>Row 2</td></tr>
  <tr><td>Row 3</td></tr>
</table>
<script>
$( "tr:first" ).css( "font-style", "italic" );
</script>
</body>
</html>

first selectorversion deprecated: 3.4

version added: 1.0jQuery( ":first" )

Additional Notes:

Demo: