You can add HTML, you just cant use double Quotes. If you want to add a link, you need to do this:
<a href='blah'>test</a>
Notice that I don't use double quotes.
You can use double if you want to, you'd just need to switch the key parser.
Eg,
var text = "<a href='http://google.com'>HTML that uses one quote for tags</a>";
var text = '<a href="http://google.com">HTML that uses double quotes for tags</a>';
Also, you have incorrect syntax.
$("#footerarea").append("<center><span class='smalltext'>"+text+"</span></center>");
Change to:
$("#footerarea").append("<div style='text-align: center;' class='smalltext'>"+text+"</divr>");