I am still not sure about your question, But If I was to send 3 values from one page , This is what I would have done,
<form id="form1" runat="server">
<div>
<input type="text" id="GhestCompanyID" value="GhestCompanyID" />
<input type="text" id="ExternalGhestID" value="ExternalGhestID" />
<input type="text" id="ExternalCellPhone" value="ExternalCellPhone" />
<input type="button" name="aaaa" value="bbbb" onclick="btnExternalPayGhest_Click(190)" />
</div>
</form>
and write script like,
function btnExternalPayGhest_Click(id) {
var GhestCompanyID = document.getElementById("GhestCompanyID").value;
var ExternalGhestID = document.getElementById("ExternalGhestID").value;
var ExternalCellPhone = document.getElementById("ExternalCellPhone").value;
if (id== 190) {
location.href = 'http://www.tkhkportal.com/Login.aspx?ReturnUrl=default.aspx?x=' + GhestCompanyID + '&y=' + ExternalGhestID + '&z=' + ExternalCellPhone;
}
else if (GhestCompanyID == 240) {
location.href = 'http://www.tkhkportal.com/Login.aspx?ReturnUrl=default.aspx?x=' + GhestCompanyID + '&y=' + ExternalGhestID + '&z=' + ExternalCellPhone;
}
}