Jquery Receive selected option and Passing it in Ajax by using $.param()

Jquery Receive selected option and Passing it in Ajax by using $.param() on the same php page

HTML

<select id="page_count" >                                          
            <option value="10">10</option>
            <option value="20">20</option>
            <option value="30">30</option>
     </select>
<hr>

<div id="log"></div>

CSS

#log{
    width: 300px;
    height: 100%;
    min-height:50px;
    border: 1px solid #eee;
    border-radius:8px;
}

#page_count{
    width:200px;
    border: 1px solid #eee;
    padding: 3px 6px;
}

JavaScript

var total_items;

$("#page_count").change(funct	ion(e){
    total_items = $(this).val();
    
    var queryParams = {"total_items": total_items};
    //inajax use dataParams in data parameter
    var dataParams = $.param(queryParams);
    
    $("#log").append( "<br>Selected => " + total_items + " -> Param : " + dataParams );
    
    $.ajax({

                        type : "POST",                  
                        url : "start_landing_page.php",                                     
                        data : dataParams,                  
                        success : function(data){
                                alert("sucess!");
                                }
                        });     
});