<!DOCTYPE html>
<html lang="en-US">
<body>
<script>
var myNumber = [1, 2, 3, 4, 5, 6, 7];
document.write(myNumber.join() +"<br>");
//join array elements with nothing
document.write(myNumber.join("") +"<br>");
//join array elements with underscore
document.write(myNumber.join("_"));
</script> </body>
</html>