CODEWITHSUNDEEP
jqueryperformance
Donald T
Donald T

Reputation: 10667

Which is faster: $(".elt", $this) or $this.find(".elt");?

var $this = $(this);

Given the above, which is faster: $(".elt", $this) or $this.find(".elt")?

I ask because the first seems a bit more concise, but if it converts to $($this).find(".elt") [sic], it seems that it could in fact be slower.

Upvotes: 1

Views: 504

Answers (2)

Šime Vidas
Šime Vidas

Reputation: 185963

The performance difference between those two is negligible.

$( 'selector', context ) is transformed into $( context ).find( 'selector' ) at the very beginning of the jQuery $() function. We are talking microseconds here (if not nanoseconds).

(I prefer the shorter form because it's... well, shorter.)

Upvotes: 3

Kevin B
Kevin B

Reputation: 95047

It is much faster to use $("#elt") since there is only one element with an id="elt" that is a valid element. (ID's MUST BE UNIQUE)

Edit: If you were only using that as an example, and the same question applies to using a class instead of an ID, Both ways should be relatively the same due to the way jquery works internally.

$(".elt", $this) converts to $this.find(".elt") which is identical to $this.find(".elt").

You may find a difference between the two after running several thousand iterations of it at once, but in normal circumstances, you are better off using the one that is easier to read.

Upvotes: 5

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