concat objects
HTML
<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
<div id="a">
</div>JavaScript
var a = [1,2,3,4,5];
var b = [6,7,8,9,0];
var c = [];
console.log(a.concat(b);
console.log(a.concat(c);
console.log('3');
console.log(a.concat([]));
$("#a").html(a.concat(b);