How do I check if checkbox is checked in PHP? [closed]

Answer 1

if(!isset($_POST['tos']))
  $this->errors[] = 'Please accept our Terms of Service.';`

What this is doing is saying if there is no 'tos' in $_POST, throw an error.

Really you should probably check this client side with javascript, before the form is sent to the server.

You could also...

<input type="checkbox" name="tos" value="accepted" checked>

And PHP:

if(isset($_POST['tos']) && $_POST['tos']==='accepted') echo 'All good'; 
else array_push($errors,'err code here'); //to add to $error array

Update

I'm not sure if you're using jQuery or not, but just for a more user friendly approach:

var tos = $('#tos');
var notice = $('.notice');
tos.on('click',function(){
  if(tos.is(':checked')){
    notice.text('Thank you.');
  }
  else{
   notice.text('Please accept our ToS to continue.');
  }
})

See a working example here. You could even halt the form all together if it's unchecked. BTW, if I remember correctly checkbox inputs only send POST data if checked.