返回值:NumberjQuery.inArray(value, array)
Search for a specified value within an array and return its index (or -1 if not found).
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1.2 新增jQuery.inArray(value, array)
value (Any) The value to search for.array (Array) An 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.
示例:
Report the index of some elements in the array.
<!DOCTYPE html>
<html>
<head>
<style>
div { color:blue; }
span { color:red; }
</style>
<script src="jquery.min.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>