Question

$(document).ready(function()
{    
    $(":input").focusout(function () {
    var a= $(this).closest("tr").attr('id');
    var b= $(this).closest("td").attr('id');
        var c = $(this).attr("value");


    $.post("database.php", { trAdress:a , tdAdress:b, value:c});

    });
});

could this code work only between <div i="bab"> </div> tags…

Answer 1

I think you really need to read about jQuery and how it works .. i suggest you start here

http://docs.jquery.com/How_jQuery_Works

In your code this line :

$(":input").focusout(function () {

is a selector $(':input') – which selects part of the DOM
and a method focusout – the method performs an action on the selected element, in your case adds an event listener. You can select just about anything on the DOM … read this section of the docs

If you have the following HTML (or something like it)

<div id="bab">
 <input etc.... />
</div>

you could use $('#bab :input') as your selector (descendant selector) – this would get all input elements within the div with an id of bab (# means use the id selector)