Member Name <input type="text" class="demo" data-prefix="JKT48_" />
<br>
Website <input type="text" class="demo" data-prefix="http://" />
<br>
Phone <input type="text" class="demo" data-prefix="+62" />

<!-- Include jQuery -->
<script src="//code.jquery.com/jquery-2.1.1.min.js"></script>

<!-- Include prefix-input.js -->
<script src="js/jquery.prefix-input.js"></script>
<script>		
$(function() {
	$(".demo").prefix();
});
</script>

<a href="https://github.com/bachors/jQuery-Prefix-Input" target="_BLANK"><img style="position: absolute; top: 0; right: 0; border: 0;" src="https://camo.githubusercontent.com/365986a132ccd6a44c23a9169022c0b5c890c387/68747470733a2f2f73332e616d617a6f6e6177732e636f6d2f6769746875622f726962626f6e732f666f726b6d655f72696768745f7265645f6161303030302e706e67" alt="Fork me on GitHub" data-canonical-src="https://s3.amazonaws.com/github/ribbons/forkme_right_red_aa0000.png"></a>