นำข้อมูลไปแสดงในปฏิทินไม่ได้ทำไงดีคะ ( fullcalendar )

<?php
header("Content-type:application/json; charset=UTF-8");          
header("Cache-Control: no-store, no-cache, must-revalidate");         
header("Cache-Control: post-check=0, pre-check=0", false);   
$con_db=mysql_connect("localhost","root","12345678") or die("Cannot connect db server");  
$select_db=mysql_select_db("project");  
if($_GET['ID']){  
    $q="SELECT * FROM borrowreturn WHERE StartDate ='".$_GET['StartDate']."'  ";  
    $q.=" AND EndDate='".$_GET['EndDate']."' ORDER by ID";  
    $qr=mysql_query($q);  
    while($rs=mysql_fetch_object($qr)){  
        $json_data[]=array(  
            "ID"=>$rs->ID,
            "project_name"=>$rs->project_name,
            "StartDate"=>$rs->StartDate,
            "EndDate"=>$rs->EndDate
        );    
    }  
}
$json= json_encode($json_data);  
if(isset($_GET['callback']) && $_GET['callback']!=""){  
echo $_GET['callback']."(".$json.");";      
}else{  
echo $json;  
}  
?>