Mix Two functions on checkboxes

[Teschio]

Hi to all,
I have a function "f(frmObj)" that was created to get the sum of values of selected checkboxes and put them in a text field "who" (every value is separated by "-")
I added also a function "check(field)" that check/uncheck all checkboxes by clicking on a button..
Now i'd like to call "f(frmObj)" into "f(frmObj)"...
example:
1)On page loaded (all checkboxes are checked) i'd like "who" to get all checkboxes values.
2)On "Select All" i'd like "who" to get all checkboxes values.
3)On "Deselect All" i'd like "who" to get empty value "".

That's my code:

<SCRIPT LANGUAGE="JavaScript">
var checkflag = "true";
function check(field) {
if (checkflag == "false") {
for (i = 0; i < field.length; i++) {
field[i].checked = true;}
checkflag = "true";
return "Deselect All"; }
else {
for (i = 0; i < field.length; i++) {
field[i].checked = false;}
checkflag = "false";
return "Select All"; }
}

function f(frmObj)
{

var strVal = "";
var el = frmObj.elements;
var nFields = el.length;
var sepStr = "-";

for ( n = 0 ; n < nFields ; n++ )
{
if (el[n].type == "checkbox" && el[n].checked)
{
if (strVal.length > 0) strVal += sepStr;
strVal += el[n].value;
}
}
document.form1.who.value = strVal;
}
</script>

<form name="form1" method="post" action="test.php">
<input type=button value="Deselect All" onClick="this.value=check(this.form.list)">
<br>
<input type=checkbox name=list value="1" checked onClick="f(this.form);">Option 1<br>
<input type=checkbox name=list value="2" checked onClick="f(this.form);">Option 2<br>
<input type=checkbox name=list value="3" checked onClick="f(this.form);">Option 3<br>
<input type=checkbox name=list value="4" checked onClick="f(this.form);">Option 4<br>
<input type=checkbox name=list value="5" checked onClick="f(this.form);">Option 5<br>

<input type=text name=who>

<input type="submit" name="Submit" value="Send">

</form>

Can anyone help me?
Thank you all...

[orion_rus]

<input type=button value="Deselect All" onClick="this.value=check(this.form.list)">
change this:
<input type=button value="Deselect All" onClick="this.value=check(this.form.list);f(this.form)">
good luck to you

[Teschio]

Thank you!