performance - Can I cache $(window) and $(document) in jQuery? -

performance - Can I cache $(window) and $(document) in jQuery? -

i read articles regarding jquery performance, , came weird questions.

can/should cache $(window)?

if did, impact resize, scroll, width, scrolltop...etc?

can/should cache $(document)?

as utilize lot of mouse actions, should var doc = $(document);?

can always cache $(this) in big block of code?

as var self = $(this);, in status self might different $(this)?

all 3 questions: yes can!

neccessery : no

better performance: maybe

you seek , benchmark. reason caching not search entire dom selector. looking document , window isn't problem because 2 root variables. caching $(this) depends on situation. see 2nd tip.

always cache parent object run queries on:

var header = $('#header'); var menu = header.find('.menu'); // or var menu = $('.menu', header);

it’s improve chain jquery methods cache selectors:

$('li.menu-item').click(function () {alert('test click');}) .css('display', 'block') .css('color', 'red') fadeto(2, 0.7);

cache elements query often:

var header = $('#header'); var divs = header.find('div'); var forms = header.find('form');

a free performance tip:

selectors fastes slowest:

id > tag > classes

jquery performance caching