SOURCE

$(function(){
	var eobj = $("li[data-index='3']");
	if(eobj.next()){
		console.log(eobj.next().text())
	} else {
		console.log("none")
	}
})

<script src="https://cdn.bootcss.com/jquery/2.2.4/jquery.js"></script>

<ul>
	<li data-index='1'>111</li>
	<li data-index='2'>222</li>
	<li data-index='3'>333</li>
</ul>

ul{
	color: #fff;
}