Is it possible to pull yoru HTML from somewhere else?

[DotCom]

to just reference it in the source like CSS and have it pull up?

 

[ronaldroe]

You can use includes from a server side language like PHP for that. AJAX will also do it.

 

[Nullified]

You can use frames, but no you cannot have a link to html like you can a css/js document. You can however do as ronald suggested an have a php include if you are trying to make generalized template files for headers/footers/colums/etc:

<?php include('header'); ?>
<div id="body">Your Page Content Goes Here</div>
<?php include('footer.php'); ?>