You could use frames assuming frames are enabled for the browser. This way you could link directly to 2 pages that are already set up. The way you should set up the frames would be like:
<html>
<head>
<title>Side-by--side Comparison</title>
</head>
<frameset cols="50%, 50%">
<noframes>
To be viewed properly, this page requires frames.
</noframes>
<frameset rows="100%">
<frame src="temp1.txt">
</frameset>
<frameset rows="100%">
<frame src="Doc1.html">
</frameset>
</frameset>
</html>