Capsi 0 Newbie Poster

Hi frnds,
I m new to ajax. I have implemented the ajax autocomplete
<ajax:autocomplete
source="tag"
target="make"
baseUrl="autocompleteTag.htm"
className="autocompleteTag"
indicator="indicator1"
minimumCharacters="1"
parser="new ResponseXmlToHtmlListParser()" />
this my partial code.

The problem is that when i press any alphabet say suppose "a", i get all names starting with "a" say amy, admin, anuj etc one below other. now when i select one of them say 'amy' the text box will display "amy,". Now when i press "a" again then it shows "amy,admin" & "amy,anuj" one below the other.
As i want to enter multiple values comma seperated. But i want the ajax to show only "admin" and "anuj" and when i select any one of this, it should append the the value previously present in text box(i.e it should append the value "amy").
It is possible to show the list but when i select the value it doesnot append the previously present value. It replaces a value..
Please reply to this...
I would be really thankful to u all..
Thanks.