Posted by OmegaJunior on 12/26/06 01:32

On Tue, 26 Dec 2006 00:47:55 +0100, Charles O'Flynn <carles@matchwalk.co=
m> =

wrote:

> Can anyone help, please?
> I am writing a program that has a drop-down list to allow the user to =
=

> change
> one of the variables. The drop-down is coded in HTML. I know how to
> refresh the screen in HTML but not in PHP.
> The idea is to re-draw the screen with one of the variables re-defined=
,
> thereby producing a completely different display. Possibly my =

> fundamental
> approach is wrong, but I'm not particularly experienced in this sort o=
f
> thing, and this is the best I can come up with. For reference, the pa=
ge =

> is
> at http://dev.matchwalk.com - click on 'Weather forecast' under 'Relat=
ed
> links'. I want to be able to alter the location to which the forecast=

> refers.
> Thanks in advance for any suggestions.
> Charles
>
>

If you already know HTML form submitting techniques, this should be =

relatively easy to understand.

In your current setup, you have a form named "weatherForm" with a "get" =
=

method, but without an action attribute. Instead, you use a javascripted=
=

"updatelocation" method that reacts to the onSelect event of the dropdow=
n =

list.

There is a set of methods named "AJAX" that allows you to load new =

information dynamically, based on javascript methods. Though this is a =

very nice way of handling it, it's also extremely cumbersome compared to=
=

the "old school" technique of simply submitting the form.

How to do it:
Add a submit input to your form and title it aptly, like "Go". Add an =

action attribute to your form, and as its value you assign the name of t=
he =

current script. So basically you're submitting the form to its own page.=


Then in the current script, before building the rest of the page, you re=
ad =

the querystring using the variable $_GET['location'] (PHP 4 and up will =
=

create this variable for you automatically because the form was =

submitted). Upon knowing the location, you choose the correct data to =

present. If that variable isn't filled in (check with =

if(isset($_GET['location'])=3D=3Dtrue)), show a default location of your=
=

choosing.

Hope this helps!

-- =

Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

[Back to original message]