Submit two forms sequentially with AJAX - ajax

Question

I'm trying to implement the answer from this thread, however I've never used AJAX.
The first form sets a variable required in the second form, once this has been set I'd like it to then redirect as per the second form (so I'm guessing the alert wants to come out of the AJAX?)
After updating with charles babbage's answer the first form Submits.
Thanks for any help, it's greatly appreciated!
<script>
$(document).ready(function() {
$("#subbut").click(function() {
$.post($("#priceselect").attr("action"), $("#priceselect").serialize(),
function() {
$.post($("#globaliris").attr("action"), $("#globaliris").serialize(),
function() {
alert('Both forms submitted');
});
});
});
});
</script>
I've put this in the head with the aim of first submitting
<form name="priceselect" id="priceselect" method="post">
<select name="price" id="mySelect" onchange="document.getElementById('selectedValue').innerHTML = this.value;">
<option value="100">Option 1</option>
<option value="120">Option 2</option>
<option value="115">Option 3</option>
<option value="135">Option 4</option>
<option value="80" >Option 5</option>
</select>
<input value="Continue" id="subbut" type="Submit" />
</form>
which should then
(isset($_POST['price']));
$price = $_POST['price'];
in the same page before redirecting to a 3rd party with the submission of
<form id="globaliris" action="https://redirect.globaliris.com/epage.cgi" method="post" class="select">
<input type=hidden name="MERCHANT_ID" value="<?=$merchantid?>">
<input type=hidden name="ORDER_ID" value="<?=$orderid?>">
<input type=hidden name="CURRENCY" value="<?=$curr?>">
<input type=hidden name="AMOUNT" value="<?=$amount?>">
<input type=hidden name="TIMESTAMP" value="<?=$timestamp?>">
<input type=hidden name="MD5HASH" value="<?=$md5hash?>">
<input type=hidden name="AUTO_SETTLE_FLAG" value="1">
<br />
<br />
</form>

Answer 1

In order to trigger the action that you have specified in the Form tag on click of a button, the button should be of type Submit and also it should be inside your form. The position of Submit button is important.
<input type="submit" value="something" id="something">
Edit(as per your new question)
If you want two form's content to be submitted to one action, just add the serialises as below:
$.post($("#priceselect").attr("action"),$("#priceselect").serialize()+$("#globaliris").serialize() ,
function() {
alert('Both forms submitted');
});
});