JavaScript variable value to PHP variable

I have a JavaScript function that creates a <div>. It uses Ajax to access the database so and creates a different <div> if the dates match. But now I want to take the 'date' variable from the JavaScript <div> that matches the database and send it through another PHP function that gets all entries with that date and echoes them out to a JQuery pop-up. What am I’m doing wrong and is there an easier way than the code below?

First AJAX call:

beforeMonth:function(date)
    {
        $.ajax({
            type: "GET",
            url: "getCalendarEvents.php",
            dataType: "json",
            data: "date="+date,
            async: false, //stop rendering the calender until eventdates is changed.
            success: function(json){
                $.fn.ical.changeEventDates(json); //this function changes the eventdates
            }   
        })
    }

getCalendarEvents.php

include ("Includes/dbConnect.php");

$_GET['date'];

$query2 = "SELECT * FROM events";
$checkevent = mysqli_query($cxn,$query2) or die("Couldn't execute query!");
$dates = array();

while ($row2 = mysqli_fetch_array($checkevent))
{
    $eventDate = $row2['eventDate'];
    $eventName = $row2['eventName'];
    $eventHost = $row2['host'];

    $dates[$eventDate] = array('title' => $eventName, 'desc' => $eventHost);

}
echo json_encode(array("dates" => $dates));
exit;

JavaScript in a separate file (just the function that creates the <div>):

if(!datejson)
{
    options.beforeDay(formatdate);
    $("table tr:last, obj").append("<td id = '"+formatdate+"'>"+i+"</td"); //add day
}
else
{
    options.beforeDay(formatdate);
    $("table tr:last, obj").append("<td class='date_has_event' id = '"+formatdate+"' name='"+formatdate+"'>"+i+"<div class='title'><a href='#' class='popup'><img src='images/facebook.png' class='popup'/></a></div>"+"<div class='events'><ul><li><span class='desc'>"+datejson.desc+"</span></li></ul></div></td"); //add day  
}

PHP in the HTML:

<div id="popupContact">  
<a href="#" id="popupContactClose">Close X</a>  
<div id="popupHeader">Events occurring on</div>  
<?php
include ("Includes/dbConnect.php");

$calendarDate=$_GET['formatdate']

$query = "SELECT * FROM events WHERE eventDate='$calendarDate'";

$check = mysqli_query($cxn,$query) or die("Couldn't execute query!");

while($row = mysqli_fetch_array($check))
{

    $id = $row['eventID'];

    echo "<div class='submit_event_list'><a href='individual_event_page_main.php?id=$id'>";
    echo $row['eventName'];

    echo " | " . $row['venue'];
    echo " | " . $row['eventDate'];

    echo "</a></div>";
    echo "<br />";

}

mysqli_close($cxn);
?>  

</div>