How to post data from a php file to another php file to add the data to database without using ajax

I have a php file (todo.php & todo.js) which collects some data from user and uses ajax to post the collected data to another php file (add.php) to be added to database . My issue is that I don't want to use ajax to post the data to the second php file (add.php). How do I change this. I have extracted the codes and shown below

//todo.js is called from todo.php to validate new todoEntry

function addToDo(){
    var descField = document.getElementById('nDesc');
    var percField = document.getElementById('nPerc');

    if( !validateField(descField) ){
        alert("Description " + errorMessage);
        return;
    }
    if( !validatePercentField(percField) ){
        alert("Percentage " + errorMessage);
        return;
    }

    //use ajax to post new entries to add.php which will add them
    ajaxCall(encodeURI('add.php?description=' + descField.value  
           + '&percentage=' + percField.value), function(response){
        if( response.status == 200 ){
            if( response.responseText.toString().indexOf
        ("success") != -1 ){
                //clear values
                descField.value = "";
                percField.value = "";

                //refresh table
                fetchToDo();
            }
            else
                alert(response.responseText);
        }
    });
    }

     From add.php:
    <?php
    session_start();

    if( !isset($_SESSION['username']) ){
        die("Your Session has expired. Please re-login to continue");
    }

    //get required data
    $description = trim(isset($_GET['description']) ? urldecode($_GET   
        ['description']) : "");
    $percentage = trim(isset($_GET['percentage']) ? urldecode($_GET
        ['percentage']) : "");

    //validate data
    if( empty($description) || empty($percentage) ){
        die("All fields are required!");
    }

    //connect to database
    include('connect.php');

    //insert data
    $stmt = $mysqli->prepare("INSERT INTO todo_entry VALUES (NULL, ?, NOW 
        (), NOW(), ?, ?)");
    $stmt->bind_param("ssi", $_SESSION['username'], $description,
         $percentage);
    $stmt->execute();

    if( $stmt->affected_rows > 0 ){
        $stmt->close();
        echo "success";
    }
    else{
        echo "An Error Occured: " . $stmt->error;
        $stmt->close();
    }

    //close database
    $mysqli->close();
    ?>