function WritetoDB(){
    alert('Reached. No problem getting here.');
    $.get("savedata.php");
}

<?php
$servername = "localhost";
$username = "root";
$password = "mysql";
$databaseName = "database";
$tableName = "table";

$conn = new mysqli($servername, $username, $password);

$A = mysqli_real_escape_string($conn, 'this is A');
$B = mysqli_real_escape_string(($conn, 'this is B'));
$C = mysqli_real_escape_string(($conn, 'this is C'));

$sql = "INSERT INTO `database`.`table` (columnA,columnB,columnC)
VALUES ('$A', '$B', '$C')";

$conn->close();

?>