2 questions about checkbox into form

Hi,

I defined a form consisting of checkboxes like:
<form>
<input type="checkbox" name=ck id=ck onclick="check(this.form)"
<input type="checkbox" name=ck id=ck onclick="check(this.form)"
....
<input type="checkbox" name=ck id=ck onclick="check(this.form)"
</form>

1) when this function is ran, if there is only ONE checkbox into the form, i
get in the first ALERT: "undefined" and the second gives a value of 0. When
there are 2 ore more, i get the exact length and the right number of checked
checkboxes..
My question is: why and how to solve this?
function check(form)
{
var total = 0;
var mx = form.ck.length;
alert(mx)

for (var x = 0; x < mx; x++)
{
if (eval("document.chk.ck[" + x + "].checked") == true)
{ total += 1 }
}
alert(total)


2) When one checkbox is checked, i would like to disabeld all the others,
because only one may be checked.
I tried different ways, but no succesfully (in the same function as above):
"impossible to affect to a result of function" (or something ..)

if (total==1)
{
for (var x = 0; x < mx; x++)
{
if (eval("document.chk.ck[" + x + "].checked") == false)
{eval("document.chk.ck[" + x + "].disabled") = true}
}
}

Thanks again for any hints
Fred

what makes you think this has anything to do with asp?

"Fred" <fff@its.gb> wrote in message
news:u#bbdzauEHA.220@TK2MSFTNGP15.phx.gbl...
> Hi,
>
> I defined a form consisting of checkboxes like:
> <form>
> <input type="checkbox" name=ck id=ck onclick="check(this.form)"
> <input type="checkbox" name=ck id=ck onclick="check(this.form)"
> ....
> <input type="checkbox" name=ck id=ck onclick="check(this.form)"
> </form>
>
> 1) when this function is ran, if there is only ONE checkbox into the form,
i
> get in the first ALERT: "undefined" and the second gives a value of 0.
When
> there are 2 ore more, i get the exact length and the right number of
checked
> checkboxes..
> My question is: why and how to solve this?
> function check(form)
> {
> var total = 0;
> var mx = form.ck.length;
> alert(mx)
>
> for (var x = 0; x < mx; x++)
> {
> if (eval("document.chk.ck[" + x + "].checked") == true)
> { total += 1 }
> }
> alert(total)
>
>
> 2) When one checkbox is checked, i would like to disabeld all the others,
> because only one may be checked.
> I tried different ways, but no succesfully (in the same function as
above):
> "impossible to affect to a result of function" (or something ..)
>
> if (total==1)
> {
> for (var x = 0; x < mx; x++)
> {
>  if (eval("document.chk.ck[" + x + "].checked") == false)
>  {eval("document.chk.ck[" + x + "].disabled") = true}
> }
> }
>
> Thanks again for any hints
> Fred
>
>
>
>

As thorpe says, this has nothing to do with ASP, and should have been posted
to a javascript or client-side scripting newsgroup, such as
.scripting.jscript, or one of the groups with "dhtml" in their names.
However, I will attempt to answer this below, so that your time will not
have been totally wasted. Please followup in the appropriate newsgroup
however. (cc'ed and Followup-to set to microsoft.public.scripting.jscript)
Fred wrote:
> Hi,
>
> I defined a form consisting of checkboxes like:
> <form>
> <input type="checkbox" name=ck id=ck onclick="check(this.form)"
> <input type="checkbox" name=ck id=ck onclick="check(this.form)"
> ....
> <input type="checkbox" name=ck id=ck onclick="check(this.form)"

You should give each checkbox a unique id, keeping the names the same:
<input type="checkbox" name=ck id=ck1 onclick="check(this.form)"
<input type="checkbox" name=ck id=ck2 onclick="check(this.form)"
....
<input type="checkbox" name=ck id=ck4 onclick="check(this.form)"


> </form>
>
> 1) when this function is ran, if there is only ONE checkbox into the
> form, i get in the first ALERT: "undefined" and the second gives a
> value of 0. When there are 2 ore more, i get the exact length and the
> right number of checked checkboxes..
> My question is: why and how to solve this?
> function check(form)
> {
> var total = 0;
> var mx = form.ck.length;
> alert(mx)
>
> for (var x = 0; x < mx; x++)
> {
> if (eval("document.chk.ck[" + x + "].checked") == true)

Get out of the habit of using eval. It is not necessary. A better technique
in this case would be:

var cks=document.getElementsByName("ck"),total = 0
for (var x = 0; x < cks.length; x++)
{
if (cks[x].checked == true)
{total += 1}
}

alert(total);


> 2) When one checkbox is checked, i would like to disabeld all the
> others, because only one may be checked.
> I tried different ways, but no succesfully (in the same function as
> above): "impossible to affect to a result of function" (or something
> ..)

The best way to do this would be to use radio buttons instead of checkboxes.
The page would handle this for you. However,

>
> if (total==1)
> {
> for (var x = 0; x < mx; x++)
> {
> if (eval("document.chk.ck[" + x + "].checked") == false)
> {eval("document.chk.ck[" + x + "].disabled") = true}
> }
> }
>

Again with the eval! ugh! Try this:

<HTML>
<HEAD>
<SCRIPT type="text/javascript">
function check(obj)
{
var cks=document.getElementsByName("ck")
for (var x = 0; x < cks.length; x++)
{
if (cks[x].id != obj.id)
{
cks[x].checked=false;
cks[x].disabled=obj.checked;
}
}
}
</SCRIPT>
</HEAD>
<BODY>
<form id="frm1" method="post">
<INPUT type="checkbox" id="ck1" name="ck" value="1" onclick="check(this)">
<INPUT type="checkbox" id="ck2" name="ck" value="2" onclick="check(this)">
<INPUT type="checkbox" id="ck3" name="ck" value="3" onclick="check(this)">
<INPUT type="checkbox" id="ck4" name="ck" value="4" onclick="check(this)">
<INPUT type="submit" value="Submit" id=submit1 name=submit1>

</form>




Bob Barrows

--
Microsoft MVP - ASP/ASP.NET
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