I don't have a problem just looking for a better way to do it

I have this html to start with

Code HTML4Strict:
<div id="container">
<div id="left">some content with form</div>
<div id="right">some other content</div>

I'm doing a ajax form submission, then on a successful result. I remove div id's left and right from container div and add a download div with a message div inside and some html

Code JavaScript:
$('#container').empty().append("<div id=\"download\"></div>");
$('#download').append("<div id=\"message\" class=\"message\">Signature successfully created</div><br /><a href=\"" + data.download_url + "\">Right click here</a>, then 'Save Link As.../Save Target As...'<br /><br /><img src=\"images/Pencil.jpg\" width=\"205\" height=\"35\" alt=\"\" /><br />Right click image, then 'Save Image as...'<br /><br />Once saved place these in your signatures folder");

Is there a better way to do the $('#download').append() ???

What I have is fine for short content but need a better solution for longer content. It also has a variable in the new content 'data.download_url'

I'm thinking along the lines of a JS equivalent to PHP

Code PHP:
$template_content = file_get_contents('template.html');

Thanks for any help in advance