I have a code here:
$length = 90;
for ($i=65; $i<=$lenght; $i++){
$out .= "<th>".chr($i)."</th>";
}
It output from A-Z;
but when I add value on $length; the next output is opening bracket " [ ".
What I want is A -Z AA, AB etc. like spreadsheet do.
or maybe someone can give me resources on how to create Google like Spreadsheet using PHP js. thanks!