checkboxes - error message

[ejwf]

I have a htnl form and code to process it
the form includes checkboxes

everything works fine if the user does select at least one of the checkboxes, but if the form is submitted without any checkboxes being ticked I get
Warning: Invalid argument supplied for foreach()

I need to be able to process the form and allow the user the option to ignore one complete set of check boxes if they so desire - how do I do this?

my code for the form is

<INPUT TYPE="CHECKBOX"  NAME="Information[]"  VALUE="Shipped" >
    Notify me when shipped<br>
    <INPUT TYPE="CHECKBOX"  NAME="Information[]"  VALUE="Built" >
    Notify me when it is built<br>
    <INPUT TYPE="CHECKBOX"  NAME="Information[]"  VALUE="Ordered" >
    Notify me when the parts are on order<br>

my code to process the form is

// amongst other radio buttons and text fields

$when = $_POST['Information']; 
foreach($when as $w)
{ 
$info .= $w.'      '; 
}

$body = " blah blah blah";

mail ("[e-mail]", "Feedback From Website", "$body", "FROM:[e-mail]");

 

[paulnaj]

Have you done any debugging?

Try putting ...

echo '<hr><b>POST vars</b>: <pre>'; print_r($_POST); echo '</pre>';

... at the top of your 'response' script to see what's being posted.

Paul.

[dalecosp]

ejwf wrote:

everything works fine if the user does select at least one of the checkboxes, but if the form is submitted without any checkboxes being ticked I get
Warning: Invalid argument supplied for foreach()

This is why most tutorials, most experts, and the PHP manual recommend that you test for the existence of a variable before using it in a calculation.

Of course, you could simply lower your error reporting level.

But it might be better to do a check with a control structure like if or perhaps maybe even [man]isset/man....

[Not_To_Smart]

I am not 100% sure of this, but I think the issue is if you do not check a checkbox then it is never submitted. So in your case 'Information[]' does not exist. There are several ways to handle this depending on what you are doing.

[ejwf]

OK,

I know that if the user ticks a check box the code works OK, and if I test the variable is echo's the array
However if the user does not tick any of the check boxes, nothing gets carried over and there is no array to use in the code..........

Back to my original question, how do I process the code to allow for both eventualities ?
- if there is an array, process it and output it in the e-mail,
- however if there is no array, don't worry about it and process it as 'no user response' in the e-mail

This is the bit I am struggling with - never come across anything like this before....
Can anyone point me in the right direction as to where to start - thanks

[khaine]

Try changing your code to

if ( is_array($when) )
{
    foreach($when as $w)
    { 
        $info .= $w.'      '; 
    }
} 
else
{
    echo "Not an array<br>\n";
}

What that does is test to see if the variable that you are going to process in the foreach is actually an array using the is_array function. If it's not you can output an error or just continue.