$('#cloneDiv').click(function(){
// get the last DIV which ID starts with ^= "klon"
var $div = $('div[id^="klon"]:last');
// Read the Number from that DIV's ID (i.e: 3 from "klon3")
// And increment that number by 1
var num = parseInt( $div.prop("id").match(/\d+/g), 10 ) +1;
// Clone it and assign the new ID (i.e: from num 4 to ID "klon4")
var $klon = $div.clone().prop('id', 'klon'+num );
// Finally insert $klon wherever you want
$div.after( $klon.text('klon'+num) );
});
<script src="https://code.jquery.com/jquery-3.1.0.js"></script>