For one or two references it will probably be irrelevant, but for
cases where you're looping over with each() it can make a meaningful
difference. A selector like $('div:not(#topo) div.home
div .subdestaque') takes between 5-20ms depending on the browser, by
saving the object in a variable you cut the whole of that time for
each use - a local variable lookup is, for performance matters,
instantaneous.cheers, - ricardo On Mar 5, 1:07 pm, "Rick Faircloth" <r...@whitestonemedia.com> wrote: > Thanks for the further input, Ricardo... > > Is there any way you can put a percentage of processing and/or time saved > by using var with elements? Especially if there is only one or two > references on a page? > > Rick > > -----Original Message----- > From: jquery-en@googlegroups.com [mailto:jquery...@googlegroups.com] On > > Behalf Of ricardobeat > Sent: Thursday, March 05, 2009 11:00 AM > To: jQuery (English) > Subject: [jQuery] Re: Simple one: difference between varXy.find(':text') and > $(varXy).find(':text') > > It's mostly done to improve performance. If you save the jQuery object in a > var you only need to find the element once (depending on the selector it's > an expensive operation), and then operate on that single object. I (and > other people) like to put a '$' in front of the var name when it contains a > jQ object, to make it clear: > > var $mySet = $('.mystuff'); //jQ object > $mySet.click(...).append(...) > > var myElement = $('#someelement')[0]; //HTML element > $(myElement).doSomething(); > > by doing $($mySet) you're unnecessarily creating a new object from the one > you have already stored. It's not really much overhead, but bloats code. > > ggerri: this.something() where 'something' is a jQuery method is usually > found in plug-ins: > > jQuery.fn.doSomething = function(){ > // in here, 'this' refers to the current jQuery object/set > //so you can use methods on it, like each > this.each(function(){ > // here, 'this' is the current element in the loop, not a jq object > //so you need to wrap it in jQ before using it > $(this).append(...) > }); > }; > > cheers, > - ricardo > > On Mar 5, 9:58 am, "Rick Faircloth" <r...@whitestonemedia.com> wrote: > > Hi, Rayn :handshake: :o) > > > I think, for shorthand notation (some say for readability, but I think > > otherwise), some set var's (variables) to represent pieces of code, for > instance: > > > var mySet = '$(mySet)' > > > and then use it as: > > > mySet.find(':text')... > > > Written in "longhand", it would be: > > > $('mySet').find(':text')... > > > When trying to read someone else's code, where this shorthand is use > > extensively, I just find it hard to decipher, since I have to trace > > all the var's down to find out what they stand for... > > > Someone please correct me if I'm wrong... > > > Rick > > > -----Original Message----- > > From: jquery-en@googlegroups.com [mailto:jquery...@googlegroups.com] > > On Behalf Of ggerri > > Sent: Thursday, March 05, 2009 7:31 AM > > To: jquery-en@googlegroups.com > > Subject: [jQuery] Re: Simple one: difference between > > varXy.find(':text') and $(varXy).find(':text') > > > Thanks Ryan :handshake: > > > so mySet.find(':text').each(...) would be right and > > $(mySet).find(':text').each(...) not? :confused: > > > In examples I often see (within an each function): $(this).something > > but also this.something > > > Still dont get the difference of use :,( > > > G > > > ryan.joyce...@googlemail.com wrote: > > > > mySet is an object or variable, $(mySet) will try to get an element > > > using the contents of mySet as the selector. > > > > On Mar 5, 10:04 am, ggerri <gerald.ressm...@ewz.ch> wrote: > > >> Hi there > > > >> thats an easy one for you ;-) > > > >> if i do: > > > >> var mySet = $('tr>td:nth-child(2n)'); > > > >> how do I use mySet? What's the difference between > > > >> mySet.find(':text') > > > >> and > > > >> $(mySet).find(':text') > > > >> Thanks :-)) > > >> GGerri > > > >> -- > > >> View this message in > > context:http://www.nabble.com/Simple-one%3A-difference-between-varXy.find%28 > %... > > >> Sent from the jQuery General Discussion mailing list archive at > > >> Nabble.com. > > > -- > > View this message in > context:http://www.nabble.com/Simple-one%3A-difference-between-varXy.find%28 > %... > > Sent from the jQuery General Discussion mailing list archive at > Nabble.com.
