将html id（存储在js变量中）发送到另一个php文件

I am trying to send data from a my index file to save.php Here is my code for sending data

function ClickToSave() {
var tobesent = CKEDITOR.instances.textToBeSaved.getData();
var pagename = document.getElementById("pagename").innerHTML;
var pagepath = document.getElementById("pagepath").innerHTML;
$.ajax({
    url :"save.php", 
    type :"POST",
    data :{
        content : tobesent,
        pagepath : pagepath,
        pagename : pagename
        }
    }).done(function(){
        window.alert("changes saved");
    });
}
</script>

I have also tried

function ClickToSave() {
        var pagename = document.getElementById("pagename").innerHTML;
        var pagepath = document.getElementById("pagepath").innerHTML;
        //var tobesent = CKEDITOR.instances.textToBeSaved.getData();
        var tobesent = document.getElementById("textToBeSaved").innerHTML;
        window.alert(tobesent);
        $.ajax({
            url : "save.php", 
            type : "POST",
            data :{
                content : tobesent,
                pagepath : pagepath,
                pagename : pagename
                }
            }).done(function(){
                window.alert("changes saved");
                check();
            });
        }

Here is my save file

<?php
  if (empty($_POST) === false){
$pagename = $_POST["pagename"];
$pagepath = $_POST["pagepath"];
$data = $_POST["content"];
$connect = new mysqli("localhost","root","","bakliwal");
$sql =  "UPDATE `bakliwal`.`pages` SET `pagecontent` = '$data' WHERE `pages`.`pagepath` = '$pagepath' AND `pages`.`pagename` = '$pagename'";
$result = $connect->query($sql);
if($result){
    $sql =  "UPDATE `bakliwal`.`pages` SET `editable`='0' WHERE  `pages`.`pagepath` = '$pagepath' AND `pages`.`pagename` = '$pagename'";
    $result = $connect->query($sql);
    }
    $sql =  "insert into `bakliwal`.`dummy` VALUES (NULL,'$data','$pagename','$pagepath')";
    $result = $connect->query($sql);

}
?>

In the first case I received an error saying "Uncaught TypeError: Cannot read property 'getData' of undefined" in the second case i received a window alert changes saved but nothing was saved in the database

Also I have used the same code(the one in first case) to send data to save.php from another file page.php and its working perfectly fine there