Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
If I know there is at most 1 such object in my DOM, should I always append :first to the selector to speed up the lookup? I’m assuming the selection engine will stop as soon as it finds 1 matching element, but I’m not sure if the filter actually slow things down a bit.
No, as
:firstis not a standard CSS pseudo-class, and using it will cause your selector to not be passed to the nativequerySelectorAll()DOM function implemented by supporting browsers (assuming you don’t use any other jQuery-only selector syntax).jQuery will take the entire selector and parse it by itself (using Sizzle, most likely), which is leagues slower than letting the browser do the work.