I am trying to create a datagrid with a checkbox at the top of each column to allow the user to turn a column off or on.

I then want to save the options to a file so that once the user sets the columnes, it will allow the user to come back to the screen without having to select the options again.

What I am doing is storing the the options in a text string,

String 00110011

0 0 1 1 0 0 1 1
NAME DATE A B C D E F

Trying to demonstrate above that the user has selected the columns with 1 above them, but I cannot get a check box to return a value.

PHP Code:

if(isset($_POST["console"])){
 $console=implode("",$_POST["console"]);
 $sql='UPDATE tbl_staff SET interface ="'.$console.'" WHERE staff_id='.$_SESSION['staff_id'];
 $result = mysql_query($sql, $link);
 if (!$result) {
  echo 'DB Error, could not query the database MySQL Error: '.mysql_error();
    exit;
 }
 $_SESSION['interface'] = $console;
 echo $console;
} 


PHP Code:

     for ($x=1;$x<strlen($_SESSION['interface']);$x++){
      $str_header=$str_header.'<td><input type="checkbox" name="console[]" value="'.$col[$x][1].'" checked="'.$col[$x][0].'" /></td>';
     } 


I should say, I cannot get an unchecked checkbox to return a value

An unchecked checkbox is not going to return anything, so you will most likely need to set a hidden input field for the total count of columns so you can iterate.

If the value of the checkboxes is a sequence then you can determine which values are missing (ie are zero):

PHP Code:

for ($x=1;$x<=strlen($_SESSION['interface']);$x++){
      $str_header=$str_header.'<td><input type="checkbox" name="console[]" value="'.$x.'" checked="'.$col[$x][0].'" /></td>';
     } 


PHP Code:

$count = strlen($_SESSION['interface']);
$consoleArr = $_POST['console'];
$consolrStr = '';
$x = 0;
for($i = 1; $i <= $count; $i++)
{
     if($consoleArr[$x] == $i)
     {
          $consoleStr .= '1';
          $x++;
     }
     else
     {
          $consoleStr .= '0';
     }
} 


I didn't test that code but I think it will get the job done. Also, I think you had an off-by-one error in your loop:

PHP Code:

for ($x=1;$x<strlen($_SESSION['interface']);$x++) 


should be

PHP Code:

for ($x=1;$x<=strlen($_SESSION['interface']);$x++) 


Thanks Nullpointer for the help.

Here is the final bit of code.

PHP Code:

if(isset($_POST["console"])){

$count = strlen($_SESSION['interface']); 
$consoleArr = $_POST["console"];
if($consoleArr[0]==1){
 $consoleStr = '1'; 
 }
else{
 $consoleStr = '2'; 
 }
$x = 1; 
for($i = 1; $i < $count; $i++) { 
     if($consoleArr[$x] == $i) 
     { 
          $consoleStr .= '1'; 
          $x++; 
     } 
     else 
     { 
          $consoleStr .= '0'; 
     } 
}  
 $sql='UPDATE tbl_staff SET interface ="'.$consoleStr.'" WHERE staff_id='.$_SESSION['staff_id'];
 $result = mysql_query($sql, $link);
 if (!$result) {
  echo 'DB Error, could not query the database MySQL Error: '.mysql_error();
    exit;
 }
 $_SESSION['interface'] = $consoleStr;
} 


One last question, since you pointed out that I should be using <= and not just <. However, when I set the value to <= it causes one more iteration and then an error. Would you then suggest that I should subtract 1 from $count before hand?