Drop down menu (syntax problem)

[MickG]

Hi,

I'm wanting to add some code to my drop down list that changes the
value of a variable depending on the choice made, ie if none is the
option selected, then the variable cost is set to zero, if standard,
then cost =3 and so on.

<select name="bookwrapp ing">
<option value="none" selected disabled>none</option>
<option value="Standard ">Standard Wrapping</option>
<option value="Deluxe"> Deluxe Wrapping</option></p>

Thanks in advance.

Michael

[Mick White]

Re: Drop down menu (syntax problem)

MickG wrote:
[color=blue]
> Hi,
>
> I'm wanting to add some code to my drop down list that changes the
> value of a variable depending on the choice made, ie if none is the
> option selected, then the variable cost is set to zero, if standard,
> then cost =3 and so on.[/color]
<select name="bookwrapp ing" onchange="if(th is.selectedInde x)cost=
+(this[this.selectedIn dex].value);">
<option value="0" selected disabled>none</option>
<option value="1">Stand ard Wrapping</option>
<option value="2">Delux e Wrapping</option>

Mick

[RobB]

Re: Drop down menu (syntax problem)

MickG wrote:[color=blue]
> Hi,
>
> I'm wanting to add some code to my drop down list that changes the
> value of a variable depending on the choice made, ie if none is the
> option selected, then the variable cost is set to zero, if standard,
> then cost =3 and so on.
>
> <select name="bookwrapp ing">
> <option value="none" selected disabled>none</option>
> <option value="Standard ">Standard Wrapping</option>
> <option value="Deluxe"> Deluxe Wrapping</option></p>
>
> Thanks in advance.
>
> Michael[/color]

Variables - more than one - *are* changed when a user manipulates a
listbox. It generally makes more sense to simply read the current value
out as needed (at run-time) with whatever (presumably a totaling)
function you're calling.

[MickG]

Re: Drop down menu (syntax problem)

My new code is
<select name="bookwrapp ing"
onchange="if(th is.selectedInde x)wrap=+(this[this.selectedIn dex].value);">
<option value ="0">none</option>
<option value="2.95">St andard Wrapping</option>
<option value="3.95">De luxe Wrapping</option>

My problem is now that I cannot get the value to return as 0, 2.95 and
3.95 work fine, but it states that 'wrap' has not been allocated a
value.

Any more help would be greatly appreciated.

Thanks

[RobG]

Re: Drop down menu (syntax problem)

MickG wrote:[color=blue]
> My new code is
> <select name="bookwrapp ing"
> onchange="if(th is.selectedInde x)wrap=+(this[this.selectedIn dex].value);">
> <option value ="0">none</option>
> <option value="2.95">St andard Wrapping</option>
> <option value="3.95">De luxe Wrapping</option>
>
> My problem is now that I cannot get the value to return as 0, 2.95 and
> 3.95 work fine, but it states that 'wrap' has not been allocated a
> value.
>
> Any more help would be greatly appreciated.
>
> Thanks[/color]

'wrap' is only modified when on-change fires. Seems 'wrap'
is a global variable, do you initialise it anywhere? If not, and
the onchange doesn't fire, then 'wrap' is never created.

It's always a bit dangerous to just let variables be created
randomly throughout a page. All globals are better created in a
single spot (for maintenance/bug fixing reasons) so initialise
'wrap' and set it to zero just inside the very first script
element in your page:

...
<script type="text/javascript">
var wrap = 0;
...

</script>

Now if the select's onchange is not called, wrap exists and is
zero.


--
Rob