I am trying to detect if the selected element is the first child with the given class with jQuery. In the example, you can see that it is the first child with class .item but the selector :first-of-type doesn't work for that because it is not the first div.

How can this be solved?

var selectedItem = $('.list').find('.item.selected');
var isFirst = selectedItem.is(':first-of-type');

console.log('Is item first? '   isFirst);

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div >
  <div ></div>
  <div >Item 1</div>
  <div >Item 2</div>
  <div >Item 3</div>
</div>

CodePudding user response：

we can use is method to check if two elements are the same or not.

so, a solution would have two variables, one is the currently selected element and one is the first element.

let selectedItem = $('.list').find('.item.selected');
let firstElement = $('.list').find('.item:first');

console.log($(selectedItem).is(firstElement)); // this returns true, false

jsfiddle

CodePudding user response：

Using jquery's .index() overload you can apply it to a predefined collection (jquery object):

var isFirst = $(".list .item").index($('.list .item.selected')) == 0;

Updated snippet:

var items = $(".list .item");
var selectedItem = $('.list .item.selected');

var isFirst = items.index(selectedItem) == 0;
console.log(isFirst)

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div >
  <div ></div>
  <div >Item 1</div>
  <div >Item 2</div>
  <div >Item 3</div>
</div>