hm I remember there is a thread about ID n CLASS here somehow it is lost (n i too lazy to dig it out), so i make a new thread here ask the same question again

where is the difference between id n class? when to use id when to use class? i experimentally used them to hold several kind of properties n both of them works pretty well, cant see the different??

a very simple explanation for understanding:
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ID is a unique and therefore can only exist only 1 time in a single html file. all the attribute that's being declare in css for ID can only be use for a single element.

CLASS is the opposite of ID. All the attribute that's being declare in css for CLASS can be use multiple times on any html elements.
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that's the definition, both actually does work well and see no difference as u said but if u check with the web standard checker, those html which has 2 same ID in a single html will return error. That's for web standard

and is better that u differentiate ID and CLASS properly as believe me, is very useful when u do some CSS modification in the future. "changing an ID attribute wont change anything else but changing CLASS attribute will affect others"

hope my explanation is clear

thanks yes clear enough!!!

id vs class play big roll in ajax

haha simply description,

u lost ur id card, it doesn matter, u still can go for class..but there's no class, how u study? lol..jk..

just id represent for 1 thing, like ur id card never able to share with other, but class, just like u're planning to attend a programming class, there's thousand sections of classes where teaching programming (for you to choose) and all are also known as programming class. haha..hope u understand what am i explaining.

lol..

what role they r playing in ajax?
haha here i comes another question: difference between 'ajax' and 'javascript'?

I was wondering what ID and CLASS are you talking about?
Yipguseng has explain it well

You can learn about AJAX in OpenDNS

For some reason, I can't even edit my own post!!!

Anyway,
AJAX doesn't enhance Javascript. It relies on it. Javascript is a client side technology. It is purely run on the browser. AJAX can be thought of as interface between the technologies.
AJAX just uses javascript to communicate with the server in the form of XML. That's all. There's no magical difference between javascript and AJAX, AJAX is an implementation of javascript.

EDIT: the correct link is this: W3schools

Still dont get what you meant...but thank you for the explaination at least you give me some idea d

Javascript and AJAX is no different at all. That why i wonder after quite some time leaving for a short time World Wide Web and suddenly come back heard about AJAX/WEB 2.0 etc. Look at the coding and realised that it is the same Javascript with wide application use only. Long time ago has build this kind of code. Just never give a name for it..haha

What being said from the first reply is true. Id should be unique in per page, i.e can only be use once. Where as class can be use repetitively.

Some might not see the importance of this, as they tend to use id instead of class again and again.

As for me, I followed this rule strictly since I'm using jQuery, a javascript framework for my works. On events such as, click, submit, etc, jQuery heavily depending on id and classes.

I believe for those who work a lot with Javascript, to say the least, would see the importance in differentiating id and class.