how to add unique classes to a div

[jon22]

basically my end goal is to hide a voucher code then reveal when clicked and open the url in a new window,

my first problem is the way the site is coded, i can't use a single jquery function because all of the instances will have the same ID/Class, so the action will cause all of the divs to reveal no matter which one is clicked.

so i need to give each div id a unique class,

here is my code:

<script>
	 $("#revealVoucher").click(function () {
    $("#voucherCode").show("slow");
    });
</script>

<div id="revealVoucher" >
    <a href="<?=$affiliate_url?>" target="_blank">Reveal Code</a>
</div>

<div id="voucherCode">
    <a href="<?=$affiliate_url?>"><?=$voucher_code?></a>
</div>

this would be perfect if each instance of this code could be given a unique class and this is where i am stuck, how could I give both ID's (revealVoucher / voucherCode) these classes, eg revealVoucher_01, revealVoucher_02 in order for them to work independently?