Try following :
$('.expandable-panel-heading').click(function (e) {
if(e.target.nodeName == 'A'){
markActiveLink(e.target)
return;
}else{
alert('123');
}
});
function markActiveLink(el) {
alert($(el).attr("id"));
}
Here is the working demo : http://jsfiddle.net/JVrNc/4/