php and multiple checkbox processing

[I like pie]

Here's the situation:

Users can send other users messages, which are stored in two different tables, users_inbox and users_outbox.

When user #1 reads his inbox, it displays all messages in the users_inbox table that have a to_id of "1". It also displays a checkbox next to each message, the code of which looks like:

echo "<td><input type=checkbox name=message value=$row[id]></td>";

$row[id] is the message's id number btw. What I want to be able to do is have it so that users can select multiple messages and then delete them. I have no idea how to go about this though.

To make matters worse, I assume that I need the name to = message[] instead of just message, but that screws up a bit of javascript I have on the page that enables users to select or deselect all messages:

<input type="button" name="CheckAll" value="Check All" onClick="checkAll(document.post.message)">
<input type="button" name="UnCheckAll" value="Uncheck All" onClick="uncheckAll(document.post.message)">

I really am lost here... and it's holding me back from doing more important things. Can somebody help me with how to go about processing this information?

[ToddW]

Correct you use message[]

I have select all, and deselect all javascript and do exactly what you want in php too.

I`ll get the code in a few for you I`m on laptop atm.

[ToddW]

PHP Code:

if (count($message) > 0) {
        for ($i=0;$i<count($message);$i++) {
                $id        = $message[$i];        
                $sql        = mysql_query("DELETE FROM inbox WHERE id=$id");
        }
} 


That's just how I like to do the variables makes it easier to read/edit hte sql for me, but you get hte idea.

[I like pie]

Thanks Todd, that works great. I'm still having trouble with the javascript though, having [] in the input seems to be screwing things up.

<SCRIPT LANGUAGE="JavaScript">

function checkAll(field)
{
for (i = 0; i < field.length; i++)
	field[i].checked = true ;
}

function uncheckAll(field)
{
for (i = 0; i < field.length; i++)
	field[i].checked = false ;
}

</script>

That's the script I'm using when calling uncheckAll(document.post.message), and it works ok when the checkboxes have the same name, which does me no good obviously. How would I re-write this to accept message[] instead of just message?

[LazyJim]

I think there are several options.

I read that PHP might work without the [] in the HTML.
All the message[] fields are not made into an array till after PHP processes the HTTP POST Request, which contains a string like the variables on the end of a URL (?var=value&another_variable=another_value)
Your message fields would look something like this:
?message[]=20&message[]=12&message[]=99&action=delete
PHP auto-magically splits them up and makes you a $_POST array of all these, and as a nice trick puts the ones ending in [] into an array (as you know).

But search the PHP web site and you'll find another global variable with the original string, which should contain all the form fields that were ticked regardless of the square-brackets[]. Examine this string with your own function and you don't need to use the [].
In other words a small extra bit of PHP should avoid re-working your Javascript/HTML.

Alternatively write a JavaScript function that finds the input elements a different way. For example give them all a class value <input class="group1" ...> then your functions get the array of all input elements and modifies any where class contains "group1" etc. something like:

function checkAll(group_name)
{
	var inputs = getElementsByTagName("INPUT");
	for (i = 0; i < inputs.length; i++)
		if ( inputs[i].class.search(group_name) ) inputs[i].checked = true;
}

[I like pie]

Phew... luckily there seems to be an easier way.

It turns out it will work if I change checkAll(document.post.message[]) to checkAll(document.post['message[]'])

Although I wonder if this isn't properly fixing the problem. But hey, it works in firefox and IE and that's good enough for me.

Thanks for your help Todd and Jim. =)

[ToddW]

If that doesn't work let me know.

I can post my Check ALl/Uncheckall JS.

[I like pie]

well it works ok, but out of curiosity, how did you do it?