first selector
Description: Selects the first matched DOM element.
version added: 1.0jQuery( ":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
:firstis a jQuery extension and not part of the CSS specification, queries using:firstcannot take advantage of the performance boost provided by the native DOMquerySelectorAll()method. To achieve the best performance when using:firstto 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-1.10.2.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>