TD contenteditable and update value in database

I have a table which i make the td's contenteditable, for the user to easily input the data needed.

Every rows and td have value of null in database. It will have value when the user will input something and it will save/update when button save is click

my php for tbody :

 <?php
$emp_name = $_SESSION["emp_name"];
$month = $_SESSION["month"];
$REMARKS = $_SESSION[""];
$date_now = date('m');
$current_day = date('d');
$sample_var=  $_SESSION["username"] ;

        try {
            $pdo = new PDO('mysql:host=localhost:3306;dbname=******;', '****', '*****' );
            $pdo->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );
            $stmt = $pdo->prepare(
                " SELECT * from tbl_assessment WHERE employeeName = '{$_SESSION['emp_name']}' "
        );
        $flag = $stmt->execute();
        if ( !$flag ) {
            $info = $stmt->errorInfo();
            exit( $info[2] );
        }
        while ( $row = $stmt->fetch( PDO::FETCH_ASSOC ) ) {

                @$tbody1 .='<tr>';
                    $tbody1 .=' <input type="hidden" id="id" value="'.$_SESSION['id'].'"/> ';
                    $tbody1 .=' <input type="hidden" id="emp_name" value="'.$_SESSION['emp_name'].'"/> ';
                    $tbody1 .=' <input type="hidden" id="teamCode" value="'.$_SESSION['teamCode'].'"/> ';
                    $tbody1 .=' <input type="hidden" id="sectionCode" value="'.$_SESSION['sectionCode'].'"/> ';


                    $tbody1 .='<td style="height:30px" contenteditable>'.$row["date"].'</td>';
                    $tbody1 .='<td style="height:30px" contenteditable>'.$row["staffName"].'</td>';
                    $tbody1 .='<td style="height:30px" contenteditable>'.$row["findings"].'</td>';
                    $tbody1 .='<td style="height:30px" contenteditable>'.$row["action"].'</td>';
                    $tbody1 .='<td style="height:30px" contenteditable>'.$row["date_accomplished"].'</td>';
                    $tbody1 .='<td><button class="btn btn-warning px-2" id="btnSaveFindings" style="color:black;font-weight:bold;" title="Save"><i class="fas fa-save" aria-hidden="true"></i></button><button class="btn btn-info px-2" id="btnEdit" style="color:black;font-weight:bold;" title="Edit"><i class="fas fa-edit" aria-hidden="true"></i></button></td>';


        @$tbody .='</tr>';
        }   
            }
        catch ( PDOException $e ) {
        echo $e->getMessage();
        $pdo = null;
        }   
?>

my html for table :

<div id="containerDiv" style="background-color:white;border-bottom:3px solid #ff6600;margin-left:50px;margin-right:50px;margin-bottom:140px;" class="animated fadeInUp">
    <div class=""  style="margin-left:15px;margin-right:15px;overflow-x:auto;" ><br>
        <button class="btn btn-default px-3" style="float:right;" id="btnAddRow" name="btnAddRow" title="Add New row"><i class="fas fa-plus" aria-hidden="true"></i></button>
        <table class="assessment" id="assessment" width="1526px" >
        <thead style="background:-moz-linear-gradient( white, gray);">
            <tr>    
                <th colspan="6" style="font-size:20px;">ASSESSMENT/FINDINGS:</th>
            </tr>
            <tr> <!---FIRST TABLE ROW--->
                <th>DATE</th>
                <th>NAME OF THE STAFF/S</th>
                <th>ASSESSMENT/FINDINGS</th>
                <th>ACTION TAKEN</th>
                <th>DATE ACCOMPLISHED</th>
                <th>ACTION</th>
            </tr>
            <tbody>
                <?php echo $tbody1; ?>
            </tbody>
        </thead>
    </table><br><br>
</div>

what would be the function of btnSaveFindings to update the value of td in database?

from TD contenteditable and update value in database