Why does randomQuestion[0] === $("#question3") evaluate to false?

Question

`

var questions = new Array($("#question1"), $("#question2"), $("#question3"))
var randomQuestion = questions.sort(() => .5 - Math.random());

console.log( randomQuestion[0] )
console.log(  $("#question3") )
if ( randomQuestion[0] === $("#question3") ){ alert("same")}
else { alert("unsame")} `

enter image description here

Why if randomQuestion[0] === $("#question3") not work ?

All condition still show alert unsame.

It's because you cannot compare jQuery objects directly. You need to compare properties of the objects - ideally an `id` if available — Rory McCrossan, Oct 13 '20 at 09:06
Why should it work? Even if `randomQuestion[0]` would contain the element with id `question3` you're comparing two distinct jQuery objects. This would only work with actual DOM nodes. — Andreas, Oct 13 '20 at 09:07
More info on [object comparison](https://stackoverflow.com/questions/201183/how-to-determine-equality-for-two-javascript-objects) — Reyno, Oct 13 '20 at 09:07

score 1 · Answer 1 · answered Oct 13 '20 at 09:12

Just like I told in the comment section, use .is() to check if the elements are same or not :)

var questions = new Array($("#question1"), $("#question2"), $("#question3"))
var randomQuestion = questions.sort(() => .5 - Math.random());

console.log(randomQuestion[0])
console.log($("#question3"))

if ((randomQuestion[0]).is($("#question3"))) {
  alert("same")
} else {
  alert("unsame")
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<div id="question1">Question 1</div>
<div id="question2">Question 2</div>
<div id="question3">Question 3</div>

score 0 · Answer 2 · answered Oct 13 '20 at 09:06

0

From what i know, you can't compare jquery objects, so try comparing DOM objects, like:

if (randomQuestion[0][0] === $('#question3')[0])

answered Oct 13 '20 at 09:06

Johnny Tee

216
2
10

score 0 · Answer 3 · answered Oct 13 '20 at 09:07

$(something) creates a jQuery object. You are creating two identical jQuery objects, but object comparison doesn't care if objects are identical, only if they are the same object.

Compare DOM elements instead:

randomQuestion[0][0] === $("#question3")[0]

Or test the ID of the element:

randomQuestion[0]).is($("#question3")

Why does randomQuestion[0] === $("#question3") evaluate to false?

3 Answers3