How to get the name, class or id of a field in a form if serialize() in javascript?

[Exequiel]

Hello friends. . ! I want to know if how to get the name, class or id of a textfield in a form if we used the serialize() function in javascript. .
example:
we have this form

<form method="post" action="javascript:;" id="form">
<input type="text" name="field_a" class="required" id="field_a"><br>
<input type="text" name="field_b" class="required" id="field_b"><br>
<input type="text" name="field_c" class="required" id="field_c"><br>
<input type="submit" value="save" id="save">
</form>

and here is our javascript or jquery.

$('#save').click(function(event){
var data = $("form#form").serialize();

//code to know the field's class, name or id,
//alert(data.fieldname);
});

How can I code to know the textfields class, name or id for a field and out put all the fields with a class="required "?
any suggestion are appreciated, thank you and advance. :)

[Dormilich]

the answer is off the top of the jQuery documentation:

The .serialize() method creates a text string in standard URL-encoded notation.

[Exequiel]

I already solved this problem, , thanl you to your reply. :)