Get a class of part it after typing. `keyup`
<p>Why i always get a value(bu0) of typing in 3 field different(<code>class="bg_units bu0"</code>, <code>class="bg_units bu1"</code>, <code>class="bg_units bu2"</code>) ?</p>

<p>I want if user typing value in field bu0 get dynamic part 2 <code>class="bg_units bu0"</code> of class (.bu0), as for other:</p>

<ul>
<li>if typing each value on field bu0 =get class=> <code>.bu0</code> </li>
<li>if typing each value on field bu1 =get class=> <code>.bu1</code> </li>
<li>if typing each value on field bu2 =get class=> <code>.bu2</code></li>
</ul>

<p><strong>EXAMPLE:</strong> <a href="http://jsfiddle.net/jJaYT/" rel="nofollow">http://jsfiddle.net/jJaYT/</a></p>

<pre><code>$('.eghamat').live('keyup',function () {
    var $this = $(this),
    $div = $this.closest('div.find_input'),
    bu_num =  '.' + $div.find('.bg_units').attr('class').split(" ")[1];
    alert(bu_num);
});
</code></pre>
