Bir Form alanındaki seçili checkboxları saymak

<form name = "myform"> 
  <input name = "myname1" type = "checkbox" value = "Red"> RED <br> 
   BLUE 
 
  <input name = "myname3" type = "checkbox" value = "Green"> GREEN <br> 
  <input name = "myname4" type = "checkbox" value = "Yellow"> YELLOW<br><br> 
  <input type = "button" value = "Click Me" onclick="cboxlist()"><br> 
  </form> 
  <script type = "text/javascript"> 
  function cboxlist(){ 
  var choice = "Seçili Yerler: \n"; 
  var total=0; 
  var x = ""; 
  for (var i=1; i<5; i++) { 
  x = eval("document.myform.myname" + i + ".value"); 
  y = eval("document.myform.myname" + i + ".checked"); 
  if (eval("y") == true){ 
  total+=1; 
  choice = choice + "  " +  x  + "\n" ; 
  }}   
  if (choice.length <= 24) { 
  choice = choice + "Seçili Yer Yok."; 
  } 
  alert (choice + "\n Adet:" + total); 
  }  
  </script>

 
  <script type = "text/JavaScript"> 
  function ct(){ 
  var t=0; 
  var theForm = document.myform; 
  for(i=0; i<theForm.elements.length; i++){ 
  if(theForm.elements[i].type == "checkbox"){ 
   if(theForm.elements[i].checked == true){ 
   t+=1; 
  }}} 
  alert(t +' adet seçilidir'); 
  } 
    </script> 
  <form name = "myform"> 
  <input name = "myn1" type = "checkbox" value = "1"> RED <br> 
  <input name = "myname2" type = "checkbox" value = "1"> BLUE <br> 
  <input name = "myname3" type = "checkbox" value = "1"> GREEN <br> 
  <input name = "myname4" type = "checkbox" value = "1"> YELLOW<br><br> 
  <input type = "button" value = "Click Me" onclick="ct()"><br> 
  </form>