//jQuery only
var selected = $('ul#mylist li').index( $('.selected',$('ul#mylist')) );

//Dirty Javascript / jQuery way
var selected = 0;
// Iterate through item in the list. If we find the selected item, return false to break out of the loop
$(‘ul#mylist li’).each(function(index){
    if ($(this).hasClass(‘selected’)){
        selected = index;
        return false;

    }
});

http://crad.tumblr.com/post/85523431/jquery-tip-how-to-break-out-of-each

Never used the index() method in jQuery but could be useful to know. Find a selected elements index when you click on it. Note the $('ul#mylist') inside the index method, gives the search some context of where to look for .selected, saves looking through all the DOM.

Find selected elements index

jquery

jQuery