how to check prime number in php code example

Example: prime number in php

<?php
function IsPrime($n)
{
 for($x=2; $x<$n; $x++)
   {
      if($n %$x ==0)
	      {
		   return 0;
		  }
    }
  return 1;
   }
$a = IsPrime(3);
if ($a==0)
echo 'This is not a Prime Number.....'."\n";
else
echo 'This is a Prime Number..'."\n";
?>