Now Solved the problem..also used below code...using the Repeater control..
<script type="text/javascript" language="javascript">
function GetRowValue(val,name) {
// hardcoded value used to minimize the code.
// ControlID can instead be passed as query string to the popup window
window.opener.getRowvaluepopup(val,name);
window.close();
}
</script>
function openpopup() {
window.open("http://localhost:3438/AutoComplete/popupPatInsurance.aspx", "List", "scrollbars=no,resizable=no,width=400,height=280");
return false;
}
function getRowvaluepopup(val,name) {
document.getElementById("ctl00_body_txtInsuranceName").value = name;
document.getElementById("ctl00_body_DivAutoCompleteInsName").value = val;
}