如何将“amp-state”提交给我在“action-xhr”上调用的webservice？

How can I submit "amp-state" to PHP webservice that I call on "action-xhr" ?

UPDATE: Let me be specific: I have:

<form method="post" action-xhr="some_web_service_url">
   <amp-state id="myState">
        <script type="application/json">
        {
            "foo": "bar"
        }
        </script>
  </amp-state>
.....
</form>

Now, how can I set foo from the amp-state as one of the arguments/values that I have in my "post" request to "some_web_service_url"? I need to pick the value from the amp-state and I cannot set it to be fixed! I cannot set it in the url query string!

</div>

You can achieve this by simply binding to [value] on a hidden form field (make sure that your value matches the one from the initial state, since amp-state is not evaluated on load):

<amp-state id="myState">
  <script type="application/json">
  {
    "foo": "bar"
  }
  </script>
</amp-state>

<form method="post" action-xhr="some_web_service_url">
  <input type="hidden" name="foo" value="bar" [value]="myState.foo">
  ...
</form>

use this code change action

<!--  in action-xhr use your action url -->
 <form class="sky-form" method="post" action-xhr="<?=SITE_PATH?>/mailto.php" target="_top"  name="enquiry">
 <!--  here add your input field -->
 </form>

</div>