What colors do you like?

red
blue
green
black

Which one is your favorite color?

red
blue
green
black

SOURCE CODE:
<html><head><title></title></head><body>

<?
if ((isset($_POST['chk1'])) && (isset($_POST['favorite']))) {
  $ck1=$_POST['chk1'];
  $ck2=$_POST['favorite'];
} else {
  $ck1="";
  $ck2="";
}
?>

<? if (($ck1 == "") && ($ck2 == "")) { ?>
   <form method="post" action="282ln08chkrad.php">
      <h2>What colors do you like?</h2> 
      <input type="checkbox" name="chk1[]" value="red">red<br>
      <input type="checkbox" name="chk1[]" value="blue">blue<br>
      <input type="checkbox" name="chk1[]" value="green">green<br>
      <input type="checkbox" name="chk1[]" value="black">black<br><br>
      <h2>Which one is your favorite color?</h2> 
      <input type="radio" name="favorite" value="red">red<br>
      <input type="radio" name="favorite" value="blue">blue<br>
      <input type="radio" name="favorite" value="green">green<br>
      <input type="radio" name="favorite" value="black">black<br><br>
      <input type="submit" value="Submit" name="btnSubmit"> 
   </form>
<? } else { ?>
   <? if (count($chk1) !=0) { ?>
      <h2>The number of colors you selected was: <? echo count($chk1) ?></h2>
      <h2>The colors you like are (values selected check boxes):</h2>

        <?
          foreach ($_POST["chk1"] as $chk1) 
          { 
            echo $chk1 . "<br>"; 
          } 
        ?>

   <? } ?>
   <h2>Your favorite color was: <? echo $_POST['favorite'] ?></h2>
<? } ?>