function CheckSubscriptionForm(){
    var sMessage;
    
   sMessage = "";
    
    if(document.getElementById("txtUserName").value == "")
    {
        sMessage = sMessage + "Username\n";
        
    }
    if (document.getElementById("txtPassword").value == "")
    {
         sMessage = sMessage + "Password\n";
    }
    if (document.getElementById("txtFirstname").value == "")
    {
         sMessage = sMessage + "First name\n";
    }
    if (document.getElementById("txtLastname").value == "")
    {
         sMessage = sMessage + "Last name\n";
    }
    if (document.getElementById("txtEmail1").value == "")
    {
         sMessage = sMessage + "Email address\n";
    }
    if (document.getElementById("txtPhone").value == "")
    {
         sMessage = sMessage + "Telephone Number";
    }
    
    
    if (sMessage != ""){
        alert("The following information is required:\n" + sMessage);
        }
}