[jQuery] .selectedIndex VS jQuery
Why doesn't $(#b6).selectedIndex = $(#s6).selectedIndex; work? (Assuming #b6 and #s6 are similar select boxes of course. Copying billing to shipping address BTW) I know it's not really how jQuery code usually works, but would like to understand why not. -- View this message in context: http://www.nabble.com/.selectedIndex-VS-jQuery-tf2806806.html#a7831040 Sent from the JQuery mailing list archive at Nabble.com. ___ jQuery mailing list discuss@jquery.com http://jquery.com/discuss/
Re: [jQuery] .selectedIndex VS jQuery
$() gets you a jQuery object, so you can use it with jQuery methods etc. To access selectedIndex you need the actual element, so try: $(#b6)[0].selectedIndex = $(#s6)[0].selectedIndex; Chris ___ jQuery mailing list discuss@jquery.com http://jquery.com/discuss/
Re: [jQuery] .selectedIndex VS jQuery
jazzle schrieb:
Why doesn't
$(#b6).selectedIndex = $(#s6).selectedIndex;
work? (Assuming #b6 and #s6 are similar select boxes of course. Copying
billing to shipping address BTW)
I know it's not really how jQuery code usually works, but would like to
understand why not.
What $(#b6) returns is a jQuery object that contains one or more
elements (nodes), e.g. the search result of the expression that you
passed in.
If you want to access DOM properties of an element you have get them out
ouf the jQuery object first. This can be done via the get(n) method or
with simple Array index notation:
var firstElem = $(div).get(0);
var secondElem = $(div)[1];
Be careful with that: It may be the case that there is no second
element, so if you try to access secondElem (which is undefined in that
case) it may throw an error:
secondElem.className = 'foo'; // may throw an error
In such cases it's better to stick to jQuery methods like each() to
prevent such errors.
Your example again (untestet):
$(#b6).get(0).selectedIndex = $(#s6).get(0).selectedIndex;
and more jQuerish (assuming that the value corresponds to the selected
index):
$('#b6').val( $(#s6).val() );
-- Klaus
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Re: [jQuery] .selectedIndex VS jQuery
Hi
I followed the discussions about 'how to make jquery more popular'
and I just want to point out that this is the kind of things that should
be learned to newcomers in a crash course.
$() is easy to understand as a steroid getElementById(), but to
understand that it returns a jQuery object belongs
more to the innards of jQuery. I'm using for time to time jQuery for 4
months and it is the kind things I'm avid to better understand.
get(0) or [1] ok got it, but will each() work ? is there a way to filter ?
Well I usually get the answer to such questions by myself, but I'd love
to see it discussed on some blogs around with pros and cons, before I
even really need it...
Ok, maybe I should write a few stuffs by myself before to tell others
what to do, but please take this as gentle suggestion, just pointing
out...
olivvv
Klaus Hartl wrote:
jazzle schrieb:
Why doesn't
$(#b6).selectedIndex = $(#s6).selectedIndex;
work? (Assuming #b6 and #s6 are similar select boxes of course. Copying
billing to shipping address BTW)
I know it's not really how jQuery code usually works, but would like to
understand why not.
What $(#b6) returns is a jQuery object that contains one or more
elements (nodes), e.g. the search result of the expression that you
passed in.
If you want to access DOM properties of an element you have get them out
ouf the jQuery object first. This can be done via the get(n) method or
with simple Array index notation:
var firstElem = $(div).get(0);
var secondElem = $(div)[1];
Be careful with that: It may be the case that there is no second
element, so if you try to access secondElem (which is undefined in that
case) it may throw an error:
secondElem.className = 'foo'; // may throw an error
In such cases it's better to stick to jQuery methods like each() to
prevent such errors.
Your example again (untestet):
$(#b6).get(0).selectedIndex = $(#s6).get(0).selectedIndex;
and more jQuerish (assuming that the value corresponds to the selected
index):
$('#b6').val( $(#s6).val() );
-- Klaus
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Re: [jQuery] .selectedIndex VS jQuery
Olivier Percebois-Garve schrieb: Hi I followed the discussions about 'how to make jquery more popular' and I just want to point out that this is the kind of things that should be learned to newcomers in a crash course. $() is easy to understand as a steroid getElementById(), but to understand that it returns a jQuery object belongs more to the innards of jQuery. I'm using for time to time jQuery for 4 months and it is the kind things I'm avid to better understand. get(0) or [1] ok got it, but will each() work ? is there a way to filter ? Well I usually get the answer to such questions by myself, but I'd love to see it discussed on some blogs around with pros and cons, before I even really need it... Ok, maybe I should write a few stuffs by myself before to tell others what to do, but please take this as gentle suggestion, just pointing out... The Getting Started guide mentions it, but not very prominent: http://jquery.bassistance.de/jquery-getting-started.html#find Somewhere around the example with form reset... Do you think it would help the generic newcomer if the guide has more prominent examples and explanations about this issue? -- Jörn Zaefferer http://bassistance.de ___ jQuery mailing list discuss@jquery.com http://jquery.com/discuss/
Re: [jQuery] .selectedIndex VS jQuery
$() is easy to understand as a steroid getElementById(), but to understand that it returns a jQuery object belongs more to the innards of jQuery. I'm using for time to time jQuery for 4 months and it is the kind things I'm avid to better understand. Do you think it would help the generic newcomer if the guide has more prominent examples and explanations about this issue? This could be automatically checked by the debug plugin, at least when used with Firefox and Firebug. John's original debug plugin wraps each method, but you could also have getter/setter methods that warned when someone tried $().disabled = true for instance. ___ jQuery mailing list discuss@jquery.com http://jquery.com/discuss/
Re: [jQuery] .selectedIndex VS jQuery
Jörn Zaefferer wrote:
Olivier Percebois-Garve schrieb:
Hi
I followed the discussions about 'how to make jquery more popular'
and I just want to point out that this is the kind of things that
should be learned to newcomers in a crash course.
$() is easy to understand as a steroid getElementById(), but to
understand that it returns a jQuery object belongs
more to the innards of jQuery. I'm using for time to time jQuery for 4
months and it is the kind things I'm avid to better understand.
get(0) or [1] ok got it, but will each() work ? is there a way to filter ?
Well I usually get the answer to such questions by myself, but I'd
love to see it discussed on some blogs around with pros and cons,
before I even really need it...
Ok, maybe I should write a few stuffs by myself before to tell others
what to do, but please take this as gentle suggestion, just pointing
out...
The Getting Started guide mentions it, but not very prominent:
http://jquery.bassistance.de/jquery-getting-started.html#find
Somewhere around the example with form reset...
Do you think it would help the generic newcomer if the guide has more
prominent examples and explanations about this issue?
Well yes. Generally speaking this among the things where the framework
is extending the language.
Chaining seemed to be one of the aspects of jquery that peoples seemed
like the most, but I did not found
a lot of literature about it. What is or is not possible in a chain ?
how to optimize it ? When is the 'e' param in blabla(function(e){
necessary ?
Documentation is great, but is kinda like an encyclopedia, I does not
really explain the logic.
As any framework jquery builds complex data structures in a snap, and
provides useful methods to handle it.
As an intermediate developer I had no problem coding rollovers before
jquery, so even if the code is neater with jquery,
that's not the point of my choice of it. I believe I'll have a wahoo!
effect with any frameworks because I can code in 3 lines some stuffs
that move but the issue to me is more about how to code in 50 lines what
would have taken 500.
I KNOW jquery can do it, but if I run into weird issues, I also know
it may be more difficult than normal coding because
I'll understand less what is happening under the hood of jquery than
what is in my code.
I am promoting jquery to a co-worker who has written a big Prototype
based application. I could not explain him exactly
what was the type of the data he was handling, nor how to do a closure
to avoid conflict with prototype (what I saw in your? tooltip). It seems
little code to do, but... in my company we cannot spent 3-4 hours
understanding something, time needs to be justified, so he made it old
school quick and dirty.
I am a php/javascript coder and used to care little about typing. What I
see with frameworks (cakephp for php and jquery for js) is that they
lead me to manipulate more complex data structures where type become
really important.
Am I going off topic ?
So to sum up:
jquery objects - chaining - closures
That's the stuffs I wanna to master in order to claim that I really feel
confident with jquery.
Now let's go back to your article...
olivvv
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Re: [jQuery] .selectedIndex VS jQuery
I think the two most confusing and frustrating things for jQuery beginners (speaking as one myself) are these: 1) Needing to use the $() operator in every statement, even if you're referring to a variable which you got from a jQuery call in the first place, as SRobertJames has mentioned ( http://www.nabble.com/this-verus-%28this%29-tf2810909.html ). 2) Not being able to use standard DOM methods on elements returned by a jQuery call, even if you reduce it to one with an #id specification or an eq(0). I wasn't aware of get(0) before, and this made me feel like I had to learn an entire new language, quirks and all, to take advantage of jQuery's features. Please don't take this as snarky. I've really enjoyed working with the library, and I'm trying to be helpful. Jörn Zaefferer wrote: Olivier Percebois-Garve schrieb: Hi I followed the discussions about 'how to make jquery more popular' and I just want to point out that this is the kind of things that should be learned to newcomers in a crash course. $() is easy to understand as a steroid getElementById(), but to understand that it returns a jQuery object belongs more to the innards of jQuery. The Getting Started guide mentions it, but not very prominent: http://jquery.bassistance.de/jquery-getting-started.html#find Somewhere around the example with form reset... Do you think it would help the generic newcomer if the guide has more prominent examples and explanations about this issue? -- Jörn Zaefferer http://bassistance.de ___ jQuery mailing list discuss@jquery.com http://jquery.com/discuss/ -- View this message in context: http://www.nabble.com/.selectedIndex-VS-jQuery-tf2806806.html#a7844427 Sent from the JQuery mailing list archive at Nabble.com. ___ jQuery mailing list discuss@jquery.com http://jquery.com/discuss/
Re: [jQuery] .selectedIndex VS jQuery
Well yes. Generally speaking this among the things where the framework
is extending the language.
Chaining seemed to be one of the aspects of jquery that peoples seemed
like the most, but I did not found
a lot of literature about it. What is or is not possible in a chain ?
how to optimize it ? When is the 'e' param in blabla(function(e){
necessary ?
Documentation is great, but is kinda like an encyclopedia, I does not
really explain the logic.
As any framework jquery builds complex data structures in a snap, and
provides useful methods to handle it.
As an intermediate developer I had no problem coding rollovers before
jquery, so even if the code is neater with jquery,
that's not the point of my choice of it. I believe I'll have a wahoo!
effect with any frameworks because I can code in 3 lines some stuffs
that move but the issue to me is more about how to code in 50 lines what
would have taken 500.
I KNOW jquery can do it, but if I run into weird issues, I also know
it may be more difficult than normal coding because
I'll understand less what is happening under the hood of jquery than
what is in my code.
I am promoting jquery to a co-worker who has written a big Prototype
based application. I could not explain him exactly
what was the type of the data he was handling, nor how to do a closure
to avoid conflict with prototype (what I saw in your? tooltip). It seems
little code to do, but... in my company we cannot spent 3-4 hours
understanding something, time needs to be justified, so he made it old
school quick and dirty.
I am a php/javascript coder and used to care little about typing. What I
see with frameworks (cakephp for php and jquery for js) is that they
lead me to manipulate more complex data structures where type become
really important.
Am I going off topic ?
So to sum up:
jquery objects - chaining - closures
That's the stuffs I wanna to master in order to claim that I really feel
confident with jquery.
Now let's go back to your article...
olivvv
Talking of this and what is needed for getjquery.org I just read an
interesting article about what a JS library should provide:
http://www.webstandards.org/2006/12/12/reducing-the-pain-of-adopting-a-javascript-library/
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Re: [jQuery] .selectedIndex VS jQuery
jquery objects - chaining - closures
That's the stuffs I wanna to master in order to claim that I really feel
confident with jquery.
The key here is that you really do need to understand javascript.
jQuery is a javascript library. It uses objects and closures. It
manages the dom and events. It provides effects and ajax
functionality. But all of this is possible without jQuery. The
beauty and power of jQuery is that it makes these things easy. But
you must still understand what they are and how they work. You need
to understand scoping rules, scope chains, and closures. You need to
understand the DOM. You need to understand these things not because
you're using jQuery but because you're programming in javascript. And
if you feel like you're already at that level then dig right in and
look at the jQuery source code. It is a great example of how to write
good javascript and it's well-documented too. Don't treat the source
like a black-box.
Regarding the jQuery object. It's just an object. Like Date or
Array. It encapsulates zero or more DOM nodes and lets you manipulate
those nodes using the jQuery API. $ is the shorthand notation for the
jQuery object.
Regarding chaining - Yes, jQuery's chaining is great. But jQuery
didn't invent chaining. It's just an OO programming concept that's
been around for ages. You'll find that most jQuery methods return
'this' which means they return the jQuery object. That lets you keep
calling more functions like this:
$('.myClass').func1().func2().func3().
Without chaining you'd have to write:
var jq = $('.myClass');
jq.func1();
jq.func2();
jq.func3();
That's the whole idea behind chaining. The documentation is quite
good so if you want to know if a method is chainable, just look it up
in the docs. If it returns a jQuery object then it's chainable.
Sorry to ramble on so long. Good luck!
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Re: [jQuery] .selectedIndex VS jQuery
This needs to be post somewhere on the jQuery site and getjquery.org very
prominently. Excellent post Mike (damn, man you're on a roll!).
On 12/12/06, Mike Alsup [EMAIL PROTECTED] wrote:
jquery objects - chaining - closures
That's the stuffs I wanna to master in order to claim that I really
feel
confident with jquery.
The key here is that you really do need to understand javascript.
jQuery is a javascript library. It uses objects and closures. It
manages the dom and events. It provides effects and ajax
functionality. But all of this is possible without jQuery. The
beauty and power of jQuery is that it makes these things easy. But
you must still understand what they are and how they work. You need
to understand scoping rules, scope chains, and closures. You need to
understand the DOM. You need to understand these things not because
you're using jQuery but because you're programming in javascript. And
if you feel like you're already at that level then dig right in and
look at the jQuery source code. It is a great example of how to write
good javascript and it's well-documented too. Don't treat the source
like a black-box.
Regarding the jQuery object. It's just an object. Like Date or
Array. It encapsulates zero or more DOM nodes and lets you manipulate
those nodes using the jQuery API. $ is the shorthand notation for the
jQuery object.
Regarding chaining - Yes, jQuery's chaining is great. But jQuery
didn't invent chaining. It's just an OO programming concept that's
been around for ages. You'll find that most jQuery methods return
'this' which means they return the jQuery object. That lets you keep
calling more functions like this:
$('.myClass').func1().func2().func3().
Without chaining you'd have to write:
var jq = $('.myClass');
jq.func1();
jq.func2();
jq.func3();
That's the whole idea behind chaining. The documentation is quite
good so if you want to know if a method is chainable, just look it up
in the docs. If it returns a jQuery object then it's chainable.
Sorry to ramble on so long. Good luck!
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Aaron Heimlich
Web Developer
[EMAIL PROTECTED]
http://aheimlich.freepgs.com
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