Copyright code in PHP

copyright.php

<?php
/*
* Adds the copyright date
*/

function copyright($start){
  	//This line formats it to display just the year
  	$year = date("Y"); 

  	if($year === $start){
  	  echo "Copyright $year";
  	}else{
  	  echo "Copyright $start - $year";
  	}
}

// To Run, where "2010" is the start of your copyright year. 
// Msut put this years date so that way next year the "start" year is already filled out. 
// Quotes around the year, "2015", are a must to turn the year into a string. 
copyright("2015");
// Copyright 2015

echo "<br />";

copyright("2010");
// Copyright 2010 - 2015
?>