How do I use colorbox to show hidden divs on my page without hardcoding?

I'm using Colorbox to show the html content of hidden divs on my page. I can get this to work perfectly with the following:

$("a.colorbox").colorbox({width:"600px", inline:true, href:"#344"});

This will show the div with the ID of 344.

However, because I'm trying to build a scalable and dynamic page with WordPress, I want to be able to grab the ID of my divs through a function, rather than hard code them in the jquery call.

I modified Jack Moore's example:

$("a[rel='example']").colorbox({title: function(){
    var url = $(this).attr('href');
    return '<a href="'+url+'" target="_blank">Open In New Window</a>';
}}); 

so that it looks like this:

$(".colorbox").colorbox({width:"600px", inline:true, href:function(){
    var elementID = $(this).attr('id');
    return elementID;
}}); 

The problem with this is that the href property of the colorbox function is looking for a string with a # mark infront of the ID. I tried various ways of concatenating the # to the front of the function, including the # in the return value, and concatenating the # to the elementID variable. No luck.

I also tried using the syntax in Jack's example (with no luck) so that my return statement looked like this:

return "#'+elementID+'";

I think my basic question is: How do I use colorbox to show hidden divs on my page without hardcoding everything?

Thanks for your help, Jiert