Hallo,

I can not manage some task

Code:
$field_name = "surname";

/* then I need to put this value to the $_POST array
something like this */

$var = $_POST[$field_name] ;

/* I tried like this but  it doesn't work 
$var = $_POST['\''.$field_name.'\'']);
could anybody write me how I can manage when the 'field_name' value is changed dynamicly

Thanks in advance