You have 2 options... (as I see it)
Option #1
Use a div that is hidden and then display it when you need it... it can be absolutly positioned on the page so it will in affect hover over your page... Since it is on the same page (document) it is easy to retrieve the info and then hide the div again...
Problems with option 1
This method will not work with netscape...
The positioning can get tricky if the page could be scrolled to various positions...
If you have underlying Select lists they will not "hide" behind your pop-up div automatically... you would have to manually hide them...
Option #2
Pop a new window and size it smaller... then on an event write the values back to the parent window.
window.open(URL, windowName[, windowFeatures])
see...
If you need to reuse the popup... like if it is a datepicker you can put the parent form #, and object name to set in a querry string and then dynamically write the save function... (see example below)
example
--------------------------
file # 1 (main.htm)
--------------------------
<html>
<head>
<script>
var win;
var nll;
function kill(){
if (!win==nll &&!win.closed()) win.close();
}
function getStuff(){
kill();
win = window.open("popup.htm","popup","width=350, height=350 "

;
win.focus();
}
</script>
</head>
<body>
<form name='frm'>
<input type='text' name='stuff'> <input type='button' value='click me to go to popup' onclick='getStuff()'>
</form>
</body>
</html>
--------------------------
file # 2 (popup.htm)
--------------------------
<html>
<head>
<script>
function save(){
//var dt;
//var cl = document.all.cal
//dt = cl.month + "/" + cl.day + "/" + cl.year
//opener.document.forms[0].ef_tvarchar_tDate_sRec.value=dt;
// for required fields make not red if filled in or red if not...
//if(opener.document.forms[0].ef_tvarchar_tDate_sRec.ValidationType){
// opener.fixMyStyle(opener.document.forms[0].ef_tvarchar_tDate_sRec);
//}
opener.document.forms[0].stuff.value = document.frm.stuff.value;
opener.focus();
window.close();
}
</script>
</head>
<body>
<form name='frm'>
<input type='text' name='stuff'> <input type='button' value='click me to put text on main page' onclick='save()'>
</form>
</body>
</html>