To Sander,
Thank you, I changed my code in accordance with your instruction.  All but one feature are functioning in Firefox.
Now, two questions, please:
 
The non-working feature is a popup calendar that I use to fill in a date field.  This code works in IE6, but fails in FireFox with "opener.fS has no properties".
<form name="fS"
   id="fS"
   action="/cgi-bin/waa1gate.isa"
   method=POST>
   
   <input type="text"
          name="m_DATE_BEGIN" >
   <input type="image"
          src="calendar.gif"
          onclick="javascript:window.open('calendar_begin.htm');">
 
calendar_begin.htm has the function popUpCalendar that uses the "opener" property to link back to the input in the original window.
   popUpCalendar(this, opener.fS.m_DATE_BEGIN, 'm/d/yyyy')
1)  What is the proper way to refer back to the variable in popUpCalendar()?
 
2)  I haven't been able to learn if inputs use the id attribute, as in <input type="text" name="MY_VAR" id="myvar">.  If so, does nesting occur and to refer to this variable, would this be the syntax: document.getElementById("fS").getElementById("myvar").value
 
Thank you, gentlemen, for sharing your wisdom.