<form action="%%=RequestParameter('PAGEURL')=%%" id="subscribeForm"
   name="subscribeForm" method="post">
   <table cellpadding="0" cellspacing="0" border="0">
     <tr>
        <td height="60" width="250">
         <font face="Verdana" size="2">Email</font>*<br />
         <input type="text" id="EmailAddress" name="EmailAddress"></td>
     </tr>
     <tr>
        <td height="60" colspan="2">
        <input name="Submit" class="submit" type="submit" value="Submit">
        </td>
        <td></td>
     </tr>
   </table>
</form>

<script language="javascript" runat="server">
     Platform.Load("Core","1");
     try{
</script>

%%[ var @subscriberKey, @emailAddress, @url, @body,
     @httppost,@apiid,@apistatusCode,@apiresponse,@apitoken,
     @accessToken, @now, @callstatus, @response, @errorMsg

     set @emailAddress = ""
     set @httppost = ""

     if RequestParameter("Submit") == "Submit" then

       set @emailAddress = RequestParameter("EmailAddress")

       set @body = CONCAT('{"email": ', CONCAT('"', @emailAddress,
       '",'),'"validators": ', '["SyntaxValidator",', '"MXValidator",',
       '"ListDetectiveValidator"',']}')

       set @apitoken = Lookup('AccessToken','AccessToken','id',1)
       set @accessToken = CONCAT('BEARER ', @apitoken)

       set @url = "https://www.exacttargetapis.com/address/v1/validateEmail"

       set @httppost = HTTPPost2(@url, "application/json", @body, true,
       @callstatus, @response, 'Authorization', @accessToken)

       RaiseError(CONCAT('The error experienced was: ',@httppost),false)

     endif
]%%

<script language="javascript" runat="server">
} catch (ex) {
     Variable.SetValue("@errorMsg", Stringify(ex))
</script>

%%[

     if RequestParameter("Submit") == "Submit" then

     var @regEx1, @resultOfRegex1

     set @errorMsg = Substring(@errorMsg,2, Subtract(Length(@errorMsg),2))

     set @regEx1 = '(401).+(Unauthorized)'

     set @resultOfRegex1 = RegExMatch(@errorMsg, @regEx1,  0)

     if Length(@resultOfRegex1) > 0 THEN

     set @now = Now()

     /* part A - Refresh AccessToken */

     set @apiid = '{"clientId": "MYCLIENTIDGOESHERE",
                    "clientSecret":"MYCLIENTSECRETGOESHERE"}'
     set @httppost =
     HTTPPost2("https://auth.exacttargetapis.com/v1/requestToken",
     "application/json", @apiid,false,@apistatusCode,@apiresponse)
     set @apitoken = Substring(@apistatusCode,17,24)
     set @accessToken = CONCAT('BEARER ', @apitoken)

     set @httppost = HTTPPost2(@url, "application/json",
     @body, true, @callstatus, @response, 'Authorization', @accessToken)

     UpsertData("AccessToken",1,"id","1","AccessToken",@apitoken)
     UpsertData("AccessToken",1,"id","1","Last Updated",@now)

     /* part B - Validate EmailAddress */

     set @body = CONCAT('{"email": ', CONCAT('"', @emailAddress,
     '",'),'"validators": ', '["SyntaxValidator",', '"MXValidator",',
     '"ListDetectiveValidator"',']}')

     set @apitoken = Lookup('AccessToken','AccessToken','id',1)
     set @accessToken = CONCAT('BEARER ', @apitoken)

     set @url = "https://www.exacttargetapis.com/address/v1/validateEmail"

     set @httppost = HTTPPost2(@url, "application/json",
     @body, true, @callstatus, @response, 'Authorization', @accessToken)

     endif

     endif

 ]%%

<script language="javascript" runat="server">
}
</script></span>

%%[ if RequestParameter("Submit") == "Submit" AND @httppost == 200 then ]%%

EmailAddress: <span style="color:darkblue;">%%=v(@emailAddress)=%%</span><br>
body: <span style="color:darkblue;">%%=v(@body)=%%</span><br>
callstatus: <span style="color:darkblue;">%%=v(@callstatus)=%%</span><br>
httppost: <span style="color:darkblue;">%%=v(@httppost)=%%</span><br><br>

%%{={{ }}=}%%

{{.datasource JSONVar type=variable}}
  {{.data}}
    { "target" : "@callstatus" }
  {{/data}}
  {{#if valid == "true"}}
    email: <span style="color:green">{{email}}</span><br>
    valid: <span style="color:green">{{valid}}</span><br>
  {{.else}}
    email: <span style="color:red">{{email}}</span><br>
    valid: <span style="color:red">{{valid}}</span><br>
    failedValidation: <span style="color:red">{{failedValidation}}</span>
  {{/if}}
{{/datasource}}

%%[ endif ]%%