Annoying JavaScript Error

[Anon]

Hello Group,

I have a page that contains a form with multiple checkboxes generated dynamically in PHP4.

ex.
<input type="checkbox" name="choice[]" value="1">
.
.
.

Goal: The user must check two boxes then press a button that will open up a window (using a javascript window.open) that contains data dependent upon the two boxes checked.

Problem: I have written javascript code to validate that the user has selected at least two items before opening the window, but since PHP requires that the '[]' be added to the end of the checkbox name, a javascript error is generated. When I remove the '[]' for testing purposes the script works fine, but I have to include it in the final version due to other functionality that is dependent on the checkbox data.

here is the javascript:

function check() {

var num_favorites = 3;
var count = 0;

for (i=0; i<num_favorites; i++) {

if (document.form.choice[].checked) {
count++
}
}

if (count == 2) {
window.open('....')
}

}


==========================================

event call: <a href="#" onClick="check()">

The error is caused by the document.form.choice[].checked, since javascript doesn't recognize it as an valid object.

Is there any way to work around this problem while keeping the php array syntax intact?


Thank you for your help,

Rich

[Anon]

but since PHP requires that the '[]' be added to the end of the checkbox
name, a javascript error is generated.

huh? it does? why is that?

--
rad

[Anon]

In order to have the form variables processed into an array automatically by PHP, you have to put put a '[]' after the name parameter in any form element that will accept multiple selections.

ex.
<input type="checkbox" name="choice[]" value="choice 1">
<input type="checkbox" name="choice[]" value="choice 2">

assuming the user checks both boxes, after you submit the form unsing a PHP script as the action PHP will generate the following array:

choice[0] = 'choice 1'
choice[1] = 'choice 2'

The problem I am having is that I have to use the form data for multiple purposes and one includes using JavaScript to open a window using certain values that are checked.

It crashes on the following statement:

if (document.my_favorites.choice[].checked) {
count++
}

since my variable name, 'choice[]', also happens to be the same syntax as a JavaScript array, Javascript is looking for an array and it can't find it. Thus, I have an invalid object.


Hope this makes sense, I'm starting to confuse myself now...🙂


Thanks,

Rich

[Anon]

Thanks to a post on the PHP-DEV board (found using geocrawler -- what a great site!!) which mentioned the solution is in the PHP FAQ section 5.9.

You can use the JavaScript numerical form element id instead.

variable = documents.form_name.elements['choice[]'];

[Anon]

Rich,

Thanks for finding the solution! I've been struggling with the same problem. And, of course, the answer is obvious once you see what the answer is...

Kevin
B-)x

P.S. I have not, however, been able to find the FAQ to which you refer. Is it on www.php.net or elsewhere?

[Anon]

Although this solves the problem from the javascript side, I do not think this is smart enough. I think PHP must allow a way to access the http_post_vars in the string form such as "?test=1;test=2;test=3" so that it can be parsed by the programmer.

Is there a way to do this?

[Anon]

for those like me that needed a clearer example of how to do the form.elements['mychkbx[]'], here is a javascript that works for me.

Script provided by Artem - http://javascript4free.by.ru
<pre>
<SCRIPT language=JavaScript>
<!-- Hide script

function doCheckAll()
{
with (document.form) {
for (var i=0; i < elements.length; i++) {
if (elements.type == 'checkbox' && elements.name == 'chkbx[]')
elements.checked = true;
}
}
}

// End script hiding --></SCRIPT>

</pre>
Hope this saves someone days of searching for a solution.

Rich wrote:

Thanks to a post on the PHP-DEV board (found using geocrawler -- what a great site!!) which mentioned the solution is in the PHP FAQ section 5.9.

You can use the JavaScript numerical form element id instead.

variable = documents.form_name.elements['choice[]'];