弹出窗口问题

Question

<script language="javascript">
function getUser(){
var struser;
struser=showModalDialog("getUser.asp",this.form,"dialogWidth:220px;dialogHeight:240px;center:1;scroll:1;help:0;status:0");
if (struser)document.form1.user_id.value=struser;
}
</script><form name="form1" action="update_apply.asp" method="post">
<input type="text" name="user_id"><input type=button value="..." onclick="getUser()">
</form>==getUser.asp==
<script language=javascript>
function myReturn(strUserNo)
{
window.returnValue=strUserNo
window.close();
}
</script>
<input type="button" height="20" value=".." name="cmdReturn" onclick="myReturn('ok');">