Escape() and Unescape()  

Escape characters
Enter a character
Enter an ASCII value

These are not as useful as they might seem. The escape() function only works on certain non-alphanumeric characters. Experiment with various punctuation marks to get a feel for the limitations of the function.
Code in the page header 
<script language="JavaScript" type="text/javascript">
<!--
function CharToASCII(paramform) {
  paramform.txtASCII.value = escape(paramform.txtChar.value)
} 

function ASCIItoChar(paramform) {
  paramform.txtChar.value = unescape(paramform.txtASCII.value)
} 
//-->
</script>
The form 

<FORM NAME="ASCIIcharForm">

<table summary="" cellpadding=5 cellspacing=0 border=2>
<tr>

<td align=right><b>Enter a character</b></td>
<td align=center><INPUT TYPE="text" NAME="txtChar" SIZE=12></td>
<td align=left>
<INPUT TYPE="button" VALUE="Convert to ASCII" 
onClick="CharToASCII(document.ASCIIcharForm)">
</td>

</tr><tr>

<td align=right><b>Enter an ASCII value</b></td>
<td align=center><INPUT TYPE="text" NAME="txtASCII" SIZE=12></td>
<td align=left>
<INPUT TYPE="button" VALUE="Convert to Char" 
onClick="ASCIItoChar(document.ASCIIcharForm)">
</td>

</tr>
</table>

</FORM>