jQuery.inArray()

jQuery.inArray( value, array ) Returns: Number

Description: Search for a specified value within an array and return its index (or -1 if not found).

  • version added: 1.2jQuery.inArray( value, array )

    valueThe value to search for.

    arrayAn array through which to search.

The $.inArray() method is similar to JavaScript's native .indexOf() method in that it returns -1 when it doesn't find a match. If the first element within the array matches value, $.inArray() returns 0.

Because JavaScript treats 0 as loosely equal to false (i.e. 0 == false, but 0 !== false), if we're checking for the presence of value within array, we need to check if it's not equal to (or greater than) -1.

Example:

Report the index of some elements in the array.

<!DOCTYPE html>
<html>
<head>
  <style>
  div { color:blue; }
  span { color:red; }
</style>
  <script src="http://code.jquery.com/jquery-latest.js"></script>
</head>
<body>
	
<div>"John" found at <span></span></div>
<div>4 found at <span></span></div>
<div>"Karl" not found, so <span></span></div>
<script>var arr = [ 4, "Pete", 8, "John" ];

$("span:eq(0)").text(jQuery.inArray("John", arr));
$("span:eq(1)").text(jQuery.inArray(4, arr));
$("span:eq(2)").text(jQuery.inArray("Karl", arr));

</script>
</body>
</html>

Demo: