How to use Javascript to set state of checkboxes defined as PHP array?

I'm dynamically creating a group of checkboxes. The values are passed to a second page where they are processed by PHP. I want to use Javascript to check all boxes or uncheck all boxes. The form has the name checkboxes:


If I were to define the checkboxes using different names without putting them into a PHP array, then I know how to use Javascript to check or uncheck all the boxes. For example, I could create the checkboxes thusly:



I could then check all the checkboxes with a function that would contain:



I could also give the checkboxes the same name and Javascript automatically creates an array, identifying each checkbox with an index it generates. Here are checkboxes with the same name:



This would generate a JS array named "same_name", the elements of which could be accessed using the indices [0] and [1].

I could check both these boxes with a function containing



So far, so good. Here's the problem. In order to have PHP on the form-processing page successfully process the checkboxes with the same name, they must be named using the PHP convention using "[]" in the name. Using this convention the boxes would be named as follows:



Here's the problem. Apparently adding the [] screws up creation of the Javascript array because I can no longer set the checked state. I get a JS error "document.checkboxes.same_name.0 is not an object". Apparently the JS array value is not created. I would appreciate any pointers as to what I'm doing wrong or for another solution. Thanks very much.

you can use the "for ... in ..." construct or access the checkboxes by their number (at least in IE) like this:

document.checkboxes['same_name'][0]

(untested, maybe document.checkboxes['same_name[]'][0] )

After posting my question, I found various other solutions posted elsewhere. Apparently lots of people run into this problem of accessing the PHP checkbox array with JS. For others looking for a solution to this problem, don't look under the heading HTML/Javascript, look under the heading PHP. I found lots of solutions at www.phpbuilder.com/forum/ in their PHP forum.

Lots of people presented quite complicated solutions. The simplest solution I found was a little script that works well for me. Here's the script:



Note: This script is for the situation in which all the checkboxes are given the same name using the [] so that PHP recognizes you are creating an array. For example: