JQuery :: For Each Statement - Hover Over Popups

I am a javascript newbie and trying to write a script to create hover-over popups for a product page. It works like a charm when I assign it a solo "div#id" and "a#id", however I need it to work on multiple objects.I can't use a classbecause then everything with the classname pops up at the same time. So each popup HAS TO have a unique ID. I am trying to write a for each statement, but it doesn't seem to be working... any ideas... or better ways to execute this...

This is the one that works (but only for one):
<script type='text/javascript'>
$(document).ready(function(){
$( 'a#popup').hover(function(){
$('div#popupBox').fadeIn(500);
},function(){
$('div#popupBox').fadeOut(500);
});
});
</script>

This is my current for each equiv (Not Working):
<script type='text/javascript'>
for (i = 1; i < 12; i++){
varthis_a='a#popup' + i;
varthis_div='div#popupBox' + i;
$(this_a).hover(function(){
$(this_div).fadeIn(500);
},function(){
$(this_div).fadeOut(500);
});
}
</script>