如何使用jQuery Ajax.Request将多个变量类型传递给php

I need to pass an array and a string to my php page. But I cannot figure out how to do this. Here is my code:

Javascript:

function processData(myVar){
  new Ajax.Request('myPage.php', {
    type: 'post',
    data: {myCmd: 'ProcessIt', addData: myVar},
      onSuccess: function(transport) {
        return transport.responseText;
      }
  });
}

PHP:

<?php
if (empty($_POST)){
 // $_POST is always empty.  Even though the type is array.
}

As my comment says, $_POST is always empty. I have tried many ways to get some values out of it, but it is just empty.

Can someone show me what I am doing wrong?

If you want send POST with prototypejs this is the form in ajax

new Ajax.Request('index/index.php', {
  method: 'POST',
  parameters: {
    'options[]': JSON.stringify({"array1" : "option1", "array2" : "option2"}),
   'option': "test"
  },
  onSuccess: function(transport){
    console.log(transport);
  }
});

I hope this help you

index.php

if(empty($_POST)){
  echo "BAD";
}else{
  echo json_encode($_POST);
}

If it's a html form POST you can do this.

<input type="text" name="nameOfInput[]">

The [] means it POSTS as an array.