How to pass the variable in the asp form to a javascript function "Validatedata()" while form submit?

<%
dim CountryCode,strNumber,strAddress,strCity,strState, strPostcode,
dim MyServID,CustRefNo
dim strServiceId,strCompany
%>

<SCRIPT LANGUAGE="JavaScript">
function Validatedata(){

var strurl, strCountry,strcompname,strcompnumber,strcompaddres s,strcompcity,strcompstate,strcompzipcode,servicet ype;
var emptyflag,CustRefNo ;
emptyflag = 0;
var t,serviceid;

if(emptyflag == 0 ){
strurl= "payforservices.asp?fromaction=4&MyServID="+servic eid+"&Country="+ strCountry +"&Number="+strcompnumber+"&Name="+ strcompname + "&Address="+strcompaddress+"&State="+strcompstate+ "&City="+strcompcity+"&Postcode="+strcompzipcode+" &CustRefNo="+CustRefNo;
location.href = strurl;
}
}
</SCRIPT>

<%
connectDB()
Set RS = Server.CreateObject("ADODB.Recordset")
RS.ActiveConnection=objConn
RS.Source=sql
RS.open
If not RS.eof then
if RS("servicetype") = "12" and RS("serviceid") = "14" then %>

<form method=post name="frmindex">

<table border=0 width=98% align=center cellspacing=0 cellpadding=2>
<TR class="formSectionHeader">
<TD colspan=2 align=left>Details</TD>

<TR class="FormSectionbody">
<td class=formLabel width=30% align=left>Service </td>
<TD width=70% class="clsMainFont" align=left><%=RS("servicedescription")%>&nbsp;</TD>
</TR>
<TR class="FormSectionbody">
<td class=formLabel width=30% align=left>Type</td>
<TD width=70% class="clsMainFont" align=left><%=RS("settingsdescription")%>&nbsp;</TD>
</TR>

<TR class="FormSectionbody">
<td class=formLabel width=30% align=left>Name</td>
<TD width=70% class="clsMainFont" align=left ><%=RS("subjectname")%>&nbsp;</TD>
</TR>
<TR class="FormSectionbody">
<td class=formLabel width=30% align=left>Subject #</td>
<TD width=70% class="clsMainFont" align=left><%=RS("subjectuniqueid")%>&nbsp;

</TR>

<TR class="FormSectionbody">
<td class=formLabel width=30% align=left>Address</td>
<TD width=70% class="clsMainFont" align=left><%=RS("subjectaddress1")%>&nbsp;<%=RS(" subjectaddress2")%>&nbsp;</TD>
</TR>
<TR class="FormSectionbody">
<td class=formLabel width=30% align=left>City</td>
<TD width=70% class="clsMainFont" align=left><%if subjectcity <> "" then%><%=RS("subjectcity")%><%end if%>&nbsp;</TD>
</TR>
<TR class="FormSectionbody">
<td class=formLabel width=30% align=left>State</td>
<TD width=70% class="clsMainFont" align=left><%if subjectstate <> "" then%>&nbsp;<%=RS("subjectstate")%><%end if%>&nbsp;</TD>
</TR>
<TR class="FormSectionbody">
<td class=formLabel width=30% align=left>Country</td>
<TD width=70% class="clsMainFont" align=left><%=GetCountrySettings(RS("subjectcountr y"))%>&nbsp;</TD>
</TR>
<TR class="FormSectionbody">
<td class=formLabel width=30% align=left>Post Code</td>
<TD width=70% class="clsMainFont" align=left>
<%if subjectzip <> "" then%>&nbsp;<%=RS("subjectzip")%><%end if%>&nbsp;</TD>

</TR>
<TR class="FormSectionbody">
<td class=formLabel width=30% align=left>Customer Ref.#</td>
<TD width=70% class="clsMainFont" name="CustRefNo" value="<%=RS("customerreferencenumber")%>" align=left><%=RS("customerreferencenumber")%>&nbsp ;</TD>
</TR>
<TR class="FormSectionbody">
<TD class="formLabel" align=left>&nbsp;</TD>
<TD><INPUT TYPE="button" value=" Next " onclick="javascript: Validatedata();" maxlength="200" id=button1 name=button1></TD>
</TR>

<%
RS.close
set RS = Nothing
disconnectDB()
%>

In your form, there is no any data to be submitted. So you can not pass the data to your JavaScript Validatedata().

And here's something that's somewhat related which I previously put together and may hopefully help clarify your thoughts in some way about mixing server-side ASP (which gets processed first) with client-side JavaScript.

It's easy to use the value of a VBScript variable in JavaScript:
document.writeln('<%= MyVBScriptVariable %>');

Or here is an example which puts the value of a VBScript variable into a JavaScript alert box:
Response.Write "<script language='JavaScript'>alert('The value is " & MyVBScriptVariable & "');</script>"

But to send the value of a JavaScript variable to VBScript, well that's another story. You could have the JavaScript fill in a hidden form field and then post the form. That way VBScript can pick up the value of the hidden form field with Request.Form("MyFieldName")

if you want to pass variables from asp form to script use innertext property. ex. tableID.tdID.innertext. This will give you the text inside the <TD></TD> tag. You should provide an ID to the TD and TABLE tag to do this.