child index number
by moalla
HTML
<ul id="mylist">
<li>1</li>
<li>2</li>
<li>3</li>
<li>4</li>
</ul>
JavaScript
$('#mylist li').bind('click', function(){
console.log($('#mylist li').index(this) );
$('#mylist li:eq('+$('#mylist li').index(this)+')').css('color','yellow');
});