Hi David,
Here is a repeat of a nifty little applet I first posted 5 or so years ago on this list:
If you insert the script that follows into a new web page, save it, and then
open it in your browser one can readily convert C and F.
<HTML>
<HEAD>
<BODY BGCOLOR="#FFFFFF">
<TITLE>Temperature Coversion</TITLE>
<H1> </H1>
<CENTER>
<TABLE BORDER=0 CELLSPACING=0 CELLPADDING=5 WIDTH="100%" >
<TR>
<TD VALIGN=TOP>
<H3>Temperature Conversion</H2>
Enter a number in either field, then
<ul><li>click outside the text box, or
<li>press the tab key.
</ul>
<form>
F:
<input type="text" name="F" value="32"
onChange="eval('C.value = ' + this.form.C_expr.value)" size="20">
<input type="hidden" name="F_expr" value="(212-32)/100 * C.value + 32 ">
C:
<input type="text" name="C" value="0"
onChange="eval('F.value = ' + this.form.F_expr.value)" size="20">
<input type="hidden" name="C_expr" value="100/(212-32) * (F.value - 32 )">
<input type=reset name=reset value=reset>
</form>
<P>
This script converts from celcius to fahrenheit and vice versa.
<P></TABLE>
</HTML>