Writing Clickable Link With 2 Variables Assigned?

I am trying to make a clickable link in JS wheres as 2 variable assigned as Image URL and Link URL. I have changed the address per forum rules, but I assure you they are valid images addresses and link addresses
var _IMAGE_URL = "fakeaddress/picture.jpg";
var _LINK_URL = "fakeaddress";
var _BANNER = "<center><a href="" + _LINK_URL + ""><img src="" + _IMAGE_URL + ""></a></center>"
var _POST_THIS = _BANNER

This is then called upon later through _POST_THIS, into a text box, buts its not working. However if I change this:
var _BANNER = "TEST<SP>" + _LINK_URL + "<SP>TEST<SP>2<SP>" + _IMAGE_URL + "<SP>TEST<SP>3"
Everything posts fine, but ofcourse just as text addresses, such as
TEST fakeaddress TEST 2 fakeaddress/picture.jpg TEST 3

So my problem is in this line, trying to post as a clickable picutre,
var _BANNER = "<center><a href="" + _LINK_URL + ""><img src="" + _IMAGE_URL + ""></a></center>"
Kept hammering away, and the correct statement would be this
var _BANNER = "<center><a<SP>href="" + _LINK_URL + ""><img<SP>src="" + _IMAGE_URL + ""></a></center>"