Problem with setting more than one values into cookies

Hello experts,

I want to set the values of my checkboxes into cookies when they are checked.
here is my code:
<script language="javascript">
function keepID(){
if (document.cookie && document.cookie != ""){
var old_cookie = document.cookie;
var fresh_data = document.myform.chkID.value;
document.cookie= old_cookie + escape(fresh_data);
}

else{
//start new cookie
fresh_data = document.myform.chkID.value;
document.cookie = "name=" + escape(fresh_data);
}

alert (unescape(document.cookie));
}
</script>

My checkboxes are moving in a loop:
<input type="checkbox" name="chkID" id="chkID" value="<?=$rowSubjects['ID']?>" onClick="keepID()">
Please help.........

 

Have you got a page were you are testing this and what is it outputing in the alert