jQuery returning null - selected option not being posted correctly?
===

this jQuery script is returning null. I've tried using other syntax for selected options but here's what I've got below:

The script works and runs correctly, allowing me to download the Excel file. However the ID is not being set correctly (via the option selected) and thus is parsing as "0".

    <script>
    //When Page Loads....
    $(document).ready(function(){
    
    // When the user finishes typing 
    // a character in the text box...
    $('#dropdown').change(function(){
        
        // Call the function to handle the AJAX.
        // Pass the value of the text box to the function.
        sendValue($(this).val());   
        
    }); 
    
    });
    // Function to handle ajax.
    function sendValue(str){
    
    // post(file, data, callback, type); (only "file" is required)
    $.post(
        
    "scripts/export_to_excel/index.php", //Ajax file
    
    { sendValue: str },  // create an object will all values
    
    //function that is called when server returns a value.
    function(data){
        $('#linkDiv').html(data.returnValue);
    }, 
    
    //How you want the data formatted when it is returned from the server.
    "json"
    );
    
    }

    </script>


Select HTML


    <p>Select event for export to Excel:</p>
    <p>
    <select name="eventIDExport" id="dropdown"> 
    <option value=0> 
    <?=$options?> 
    </select>
    </p>
    <?php var_dump($_POST['eventIDExport']); ?>
    <div id="linkDiv"></div>