Confused by a javascript problem, event handlers not working as expected/desired

[Deryck]

Hello,

I have been modifying some javascript shopping basket code and have run into
a problem. I have produced a subset of the HTML/JS that shows the problem
and placed it here:

http://dusrc.org/js_test.html

The problem is described on that page but basically 2 event handlers are
being called when I would expect just one to be called.

If someone could explain what I am doing wrong then I would be very
grateful.

Thanks

Deryck

[VK]

1) <input type="image"> is equal by functionality to <input="submit" >
(except it lets you track the click coords within the image)
So except some rare cases, it is always better to use old good linked image

2) If a form contains only one single-line text box, pressing <Enter> within
this box is equal to submit() action.

3) onChange event is called only after the input lost its focus. Evidently
by pressing <Enter> within the textbox you don't remove the focus, so
onChange is never called.
Change the textbox value and click anywhere on the page to see your problem.

You should re-think your model, it's too confusing for browsers.

The best would be:

<form onSubmit="someG lobalCheckOf(th is)">

[Deryck]

"VK" <sc**********@y ahoo.com> wrote in message
news:41******** *************** @news.freenet.d e...

1) <input type="image"> is equal by functionality to <input="submit" >
(except it lets you track the click coords within the image)
So except some rare cases, it is always better to use old good linked
image

2) If a form contains only one single-line text box, pressing <Enter>
within
this box is equal to submit() action.

3) onChange event is called only after the input lost its focus. Evidently
by pressing <Enter> within the textbox you don't remove the focus, so
onChange is never called.
Change the textbox value and click anywhere on the page to see your
problem.

Thanks for the above, very educational.
You should re-think your model, it's too confusing for browsers.

It confuses me too!
The best would be:

<form onSubmit="someG lobalCheckOf(th is)">

OK, Thanks again for replying.

Deryck

[Michael Winter]

On Thu, 2 Dec 2004 13:02:38 -0000, Deryck <de****@REMOVEl onghope.co.uk>
wrote:

[snip]

If someone could explain what I am doing wrong then I would be very
grateful.

You're not doing anything wrong. An image INPUT is a form of submit button
so pressing <Enter> whilst a form control has focus will cause the form to
submit.

As for the errors in Firefox, they would seem to be caused by something
the browser itself is doing, not your actions.

Mike

--
Michael Winter
Replace ".invalid" with ".uk" to reply by e-mail.

[Michael Winter]

On Thu, 2 Dec 2004 16:19:03 +0100, VK <sc**********@y ahoo.com> wrote:

1) <input type="image"> is equal by functionality to <input="submit" >
(except it lets you track the click coords within the image)
So except some rare cases, it is always better to use old good linked
image

I hope you don't mean

<a ... onclick="<formR ef>.submit();"> ...</a>

It that was you're intent, I'd argue that it is *only* in some rare cases
that using a link is better.

[snip]

Mike

--
Michael Winter
Replace ".invalid" with ".uk" to reply by e-mail.

[VK]

> I hope you don't mean

<a ... onclick="<formR ef>.submit();"> ...</a>

I'm too old to take a sin like that on my soul :-))

<a href="void(0)" onClick="someVa lueCheckFun()">
As I remember, it's actually should be
href="someValue CheckFun();canc elBubble=true">
but here we having a standard situation of an old dog and a new trick :-))

[Michael Winter]

On Thu, 2 Dec 2004 18:04:20 +0100, VK <sc**********@y ahoo.com> wrote:

[snip]

As I remember, it's actually should be
href="someValue CheckFun();canc elBubble=true">
but here we having a standard situation of an old dog and a new trick
:-))

The "correct" way is along the lines of

<a href="somewhere-useful.html"
onclick="/* ... */;return false;">...</a>

where somewhere-useful.html is a page you can use to perform the same
thing via the server which the script should have accomplished.

If the script action may fail during execution (due to a missing feature,
for example) the return value should be determined by that script.
The point I was trying to make was that using a link would mean that
action would (probably[1]) become dependent upon scripting.

Mike
[1] If nothing but an instruction and a session id needs to be sent to the
server, a link could handle that fine, but if other information needs to
be sent too, only a form submission would do.

--
Michael Winter
Replace ".invalid" with ".uk" to reply by e-mail.

[VK]

The "correct" way is along the lines of

<a href="somewhere-useful.html"
onclick="/* ... */;return false;">...</a>

Thanks, this is what I meant.

And the outdated way (in case anyone follows this thread) is
<a href="javascrip t:void(0)" ... >

I missed "javascript :" in my OP, but doesn't matter: your way is indeed more
functional.