Which control changed?

[Steve Swift]

I don't have a particular webpage to point you to; I thought about this
whilst walking my dog this morning and don't have an example page. That
said, this question doesn't really require a "working" example.

I have a form with two <SELECTcontrols. Both contain:
onChange="this.form.submit()"

So whichever one changes, my POST data contains both elements. How can I
know which one changed?

My idea is to include this in the form:
<INPUT TYPE=HIDDEN NAME=CONTROL VALUE="">

Then to change each onChange to something like this:
onChange="this.form.CONTROL.value='CONTROL_A';this .form.submit()"
where I'd use the name of the control in place of CONTROL_A of course.

So now I'll have an additional "CONTROL" value in my POST data telling
me which control changed.

Is this a workable solution? Is there a better way of doing things?

--
Steve Swift
http://www.swiftys.org.uk/swifty.html
http://www.ringers.org.uk

[Randy Webb]

Steve Swift said the following on 11/15/2007 4:17 AM:

I don't have a particular webpage to point you to; I thought about this
whilst walking my dog this morning and don't have an example page. That
said, this question doesn't really require a "working" example.

I have a form with two <SELECTcontrols. Both contain:
onChange="this.form.submit()"

So whichever one changes, my POST data contains both elements. How can I
know which one changed?

My idea is to include this in the form:
<INPUT TYPE=HIDDEN NAME=CONTROL VALUE="">

Then to change each onChange to something like this:
onChange="this.form.CONTROL.value='CONTROL_A';this .form.submit()"
where I'd use the name of the control in place of CONTROL_A of course.

So now I'll have an additional "CONTROL" value in my POST data telling
me which control changed.

Is this a workable solution? Is there a better way of doing things?

A more reliable solution would be to put the default values of the
selects lists into the page you submit to. Then compare them to the
submitted values.
--
Randy
Chance Favors The Prepared Mind
comp.lang.javascript FAQ - http://jibbering.com/faq/index.html
Javascript Best Practices - http://www.JavascriptToolbox.com/bestpractices/

[Steve Swift]

Julien wrote:

...
The name of the changed select box will be passed to in the
QUERY_STRING environment variable that you can read server side, this
even if your form is submitted via "POST".

Thanks, I'll take a look at that mechanism. I'm not expert at reading
JavaScript, so I'll have fun working out how it operates; it doesn't
look too difficult for me.

--
Steve Swift
http://www.swiftys.org.uk/swifty.html
http://www.ringers.org.uk