If called from within a function, the return()
    statement immediately ends execution of the current function, and
    returns its argument as the value of the function
    call. return() will also end the execution of
    an eval() statement or script file.
   
    If called from the global scope, then execution of the current
    script file is ended. If the current script file was
    include()ed or require()ed,
    then control is passed back to the calling file. Furthermore, if
    the current script file was include()ed, then
    the value given to return() will be returned as
    the value of the include() call. If
    return() is called from within the main script
    file, then script execution ends. If the current script file was
    named by the auto_prepend_file or auto_append_file
    configuration options in php.ini,
    then that script file's execution is ended.
   
For more information, see Returning values.
   
    
Note: 
      Note that since return() is a language
      construct and not a function, the parentheses surrounding its
      arguments are only required if the argument
      contains an expression. It is common to leave them out while returning a
      variable, and you actually should as PHP has less work to do in this
      case.
     
Note: 
      You should never use parentheses around your return
      variable when returning by reference, as this will not work. You can
      only return variables by reference, not the result of a statement. If
      you use return ($a); then you're not returning a
      variable, but the result of the expression ($a)
      (which is, of course, the value of $a).