Paste code

<html>
<head>
[removed]
function process() {
document.getElementById('tmpslt').length = 0;
var jstmp_txt = document.getElementById('tmptxt').value;
if (document.getElementById('tmpchk').checked==true)
 {
  var jstmp_arr = jstmp_txt.split(",");
  for (i=0;i<jstmp_arr.length;i++)  
  {
   var x.text = jstmp_arr[i];
   var x.value = jstmp_arr[i];
   document.getElementById("tmpslt").options.add(x);
  }
 }
}
[removed]
</head>
<body>
<form method="POST">
<input type="text" name="tmptxt" id="tmptxt">
<input type="checkbox" name="tmpchk" id="tmpchk"> Add It to drop down<br>
<select name="tmpslt" id="tmpslt">
</select>
</form>
</body>
</html>