How to comment inside a string in PHP

$var = "a
  b ".// I want to comment here but it becomes a string instead."  
  "c";

echo $var;

Only possible with concatenation and a comment:

$var = "a\n" .
//     "b\n" .
       "c";

you can also write your code like this. If you want multi line you can use \n at after string.

$string = 'First';
$string .= 'Comment section ';//this where you can comment
$string .= 'Last';