Question

I have an application where the user displays their assessment name, date and time in the relevant text inputs. Now what happens is that when the user submits the form, it displays a confirmation.

Below is the code (editsessionadmin.php):

 <script>
    function showConfirm(){

    var examInput = document.getElementById('newAssessment').value;
    var dateInput = document.getElementById('newDate').value;
    var timeInput = document.getElementById('newTime').value;

    var confirmMsg=confirm("Are you sure you want to update the following:" + "\n" + "Exam: " + examInput +  "\n" + "Date: " + dateInput + "\n" + "Time: " + timeInput);

    }


    </script>   

    <?php

    $sessionquery = "
    SELECT SessionId, SessionName, SessionDate, SessionTime, ModuleId
    FROM Session
    WHERE
    (ModuleId = ?)
    ORDER BY SessionName 
    ";

    $sessionqrystmt=$mysqli->prepare($sessionquery);
    // You only need to call bind_param once
    $sessionqrystmt->bind_param("s",$moduleId);
    // get result and assign variables (prefix with db)

    $sessionqrystmt->execute(); 

    $sessionqrystmt->bind_result($dbSessionId,$dbSessionName,$dbSessionDate,$dbSessionTime, $dbModuleId);

    $sessionqrystmt->store_result();

    $sessionnum = $sessionqrystmt->num_rows();   

    if($sessionnum ==0){
    echo "<p>Sorry, You have No Assessments under this Module</p>";
    } else { 

    $sessionHTML = '<select name="session" id="sessionsDrop">'.PHP_EOL;
    $sessionHTML .= '<option value="">Please Select</option>'.PHP_EOL;  

    while ( $sessionqrystmt->fetch() ) {
       if(time() > strtotime($dbSessionDate." ".$dbSessionTime)){
             $class = 'red';
        } else {
             $class = 'green';
        }
    $sessionHTML .= sprintf("<option value='%s' style='color: %s'>%s - %s - %s</option>", $dbSessionId, $class, $dbSessionName, date("d-m-Y",strtotime($dbSessionDate)), date("H:i",strtotime($dbSessionTime))) . PHP_EOL;  
    }


    $sessionHTML .= '</select>';


    $assessmentform = "<form action='".htmlentities($_SERVER['PHP_SELF'])."' method='post'>
    <p><strong>Assessments:</strong> {$sessionHTML} </p>   
    </form>";

    echo $assessmentform;

    }



    $editsession = "<form action=".htmlentities($_SERVER['PHP_SELF'])." method='post' id='updateForm'>

        <p><strong>New Assessment's Date/Start Time:</strong></p>
        <table>
        <tr>
        <th>Assessment:</th>
        <td><input type='text' id='newAssessment' name='Assessmentnew' readonly='readonly' value='' /> </td>
        </tr>
        <tr>
        <th>Date:</th> 
        <td><input type='text' id='newDate' name='Datenew' readonly='readonly' value='' /> </td>
        </tr>
        <tr>
        <th>Start Time:</th> 
        <td><input type='text' id='newTime' name='Timenew' readonly='readonly' value=''/><span class='timepicker_button_trigger'><img src='Images/clock.gif' alt='Choose Time' /></span> </td>
        </tr>
        </table>
        <div id='datetimeAlert'></div>

        <p><input id='updateSubmit' type='submit' value='Update Date/Start Time' name='updateSubmit' onClick='myClickHandler(); return false;'/></p>

        </form>
    ";

    echo $editsession;


    }

    ?>

    <script type="text/javascript">

    function myClickHandler(){ 
         if(editvalidation()){ 
                    showConfirm(); 
         } 
    }

    </script>

Now I want to run an UPDATE command to update the exam’s date and time in the database after the user has confirmed the confirmation and compile a SELECT query so that if the update happened, then echo it was a success, else echo there was an error.

My question is first of all is the code below correct and second of all where do I place this code so that it runs the commands after the confirmation has been confirmed?

 <?php

    $sessionname = (isset($_POST['Assessmentnew'])) ? $_POST['Assessmentnew'] : ''; 
    $sessiondate = (isset($_POST['Datenew'])) ? $_POST['Datenew'] : ''; 
    $sessiontime = (isset($_POST['Timenew'])) ? $_POST['Timenew'] : ''; 

        $updatesql = "UPDATE Session SET SessionDate = ?, SessionTime = ? WHERE SessionName = ?";                                           
        $update = $mysqli->prepare($updatesql);
        $update->bind_param("sss", $sessiondate, $sessiontime, $sessionname);
        $update->execute();

       $query = "SELECT SessionName, SessionDate, SessionTime FROM Session WHERE SessionName = ?";
       // prepare query
       $stmt=$mysqli->prepare($query);
       // You only need to call bind_param once
       $stmt->bind_param("sss", $sessionname, $sessiondate, $sessiontime);
       // execute query
       $stmt->execute(); 
       // get result and assign variables (prefix with db)
       $stmt->bind_result($dbSessionName, $dbSessionDate, $dbSessionTime);
       //get number of rows
       $stmt->store_result();
       $numrows = $stmt->num_rows();

       if ($numrows == 1){

           echo "<span style='color: green'>Your Assessment's new Date and Time have been updated</span>";

       }else{

           echo "<span style='color: red'>An error has occurred, your Assessment's new Date and Time have not been updated</span>";
    ?>

UPDATE:

Below is code for editsessionadmin.php

<script>
function showConfirm(){

var examInput = document.getElementById('newAssessment').value;
var dateInput = document.getElementById('newDate').value;
var timeInput = document.getElementById('newTime').value;

var confirmMsg=confirm("Are you sure you want to update the following:" + "\n" + "Exam: " + examInput +  "\n" + "Date: " + dateInput + "\n" + "Time: " + timeInput);

if (confirmMsg==true)
{
submitform();   
}
}

function submitform()
{

$.post("updatedatetime.php", $("#updateForm").serialize() ,function(data){
var updateFormO = document.getElementById("updateForm");
updateFormO.submit();
}); 

}
</script>   

<?php
    $sessionquery = "
        SELECT SessionId, SessionName, SessionDate, SessionTime, ModuleId
        FROM Session
        WHERE
        (ModuleId = ?)
        ORDER BY SessionName 
        ";

        $sessionqrystmt=$mysqli->prepare($sessionquery);
        // You only need to call bind_param once
        $sessionqrystmt->bind_param("s",$moduleId);
        // get result and assign variables (prefix with db)

        $sessionqrystmt->execute(); 

        $sessionqrystmt->bind_result($dbSessionId,$dbSessionName,$dbSessionDate,$dbSessionTime, $dbModuleId);

        $sessionqrystmt->store_result();

        $sessionnum = $sessionqrystmt->num_rows();   

        if($sessionnum ==0){
        echo "<p>Sorry, You have No Assessments under this Module</p>";
        } else { 

        $sessionHTML = '<select name="session" id="sessionsDrop">'.PHP_EOL;
        $sessionHTML .= '<option value="">Please Select</option>'.PHP_EOL;  

        while ( $sessionqrystmt->fetch() ) {
           if(time() > strtotime($dbSessionDate." ".$dbSessionTime)){
                 $class = 'red';
            } else {
                 $class = 'green';
            }
        $sessionHTML .= sprintf("<option value='%s' style='color: %s'>%s - %s - %s</option>", $dbSessionId, $class, $dbSessionName, date("d-m-Y",strtotime($dbSessionDate)), date("H:i",strtotime($dbSessionTime))) . PHP_EOL;  
        }

        $sessionHTML .= '</select>';

        $assessmentform = "<form action='".htmlentities($_SERVER['PHP_SELF'])."' method='post'>
        <p><strong>Assessments:</strong> {$sessionHTML} </p>   
        </form>";

        echo $assessmentform;

        }



        $editsession = "<form action=".htmlentities($_SERVER['PHP_SELF'])." method='post' id='updateForm'>

            <p><strong>New Assessment's Date/Start Time:</strong></p>
            <table>
            <tr>
            <th>Assessment:</th>
            <td><input type='text' id='newAssessment' name='Assessmentnew' readonly='readonly' value='' /> </td>
            </tr>
            <tr>
            <th>Date:</th> 
            <td><input type='text' id='newDate' name='Datenew' readonly='readonly' value='' /> </td>
            </tr>
            <tr>
            <th>Start Time:</th> 
            <td><input type='text' id='newTime' name='Timenew' readonly='readonly' value=''/><span class='timepicker_button_trigger'><img src='Images/clock.gif' alt='Choose Time' /></span> </td>
            </tr>
            </table>
            <div id='datetimeAlert'></div>

            <p><input id='updateSubmit' type='submit' value='Update Date/Start Time' name='updateSubmit' onClick='myClickHandler(); return false;'/></p>

            </form>
        ";

        echo $editsession;


        }

        ?>

        <script type="text/javascript">

        function myClickHandler(){ 
             if(editvalidation()){ 
                        showConfirm(); 
             } 
        }

        </script>

In the above code I added a jquery/ajax function submitform() where after the confirmation it will perform a post in the background to the updatedatetime.php page. There is where it displays the update and select statments. Problem is that it is not doing the update or displaying the echo in the editsessionadmin.php page

Below is code for updatedatetime.php:

    <?php

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

  /* check connection */
  if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    die();
  }

    $sessionname = (isset($_POST['Assessmentnew'])) ? $_POST['Assessmentnew'] : ''; 
    $sessiondate = (isset($_POST['Datenew'])) ? $_POST['Datenew'] : ''; 
    $sessiontime = (isset($_POST['Timenew'])) ? $_POST['Timenew'] : ''; 

    $updatesql = "UPDATE Session SET SessionDate = ?, SessionTime = ? WHERE SessionName = ?";                                           
    $update = $mysqli->prepare($updatesql);
    $update->bind_param("sss", $sessiondate, $sessiontime, $sessionname);
    $update->execute();

    $query = "SELECT SessionName, SessionDate, SessionTime FROM Session WHERE SessionName = ?";
    // prepare query
    $stmt=$mysqli->prepare($query);
    // You only need to call bind_param once
    $stmt->bind_param("sss", $sessionname, $sessiondate, $sessiontime);
    // execute query
    $stmt->execute(); 
    // get result and assign variables (prefix with db)
    $stmt->bind_result($dbSessionName, $dbSessionDate, $dbSessionTime);
    //get number of rows
    $stmt->store_result();
    $numrows = $stmt->num_rows();

    if ($numrows == 1){

    echo "<span style='color: green'>Your Assessment's new Date and Time have been updated</span>";

    }else{

    echo "<span style='color: red'>An error has occured, your Assessment's new Date and Time have not been updated</span>";



            ?>

Answer 1

PHP runs on the server, the user giving the confirmation is on the client. That means you have to use javascript/Jquery to trigger an event when the user gives his confirmation, then call a php that does the UPDATES or other query. This can be done with a AJAX call, or just submiting a form or with a url redirection.

So it should be like this:

1. First A.php that gets the form submited with the user data, does some queries and displays the confirmation text. This also has javascript code to submit the confirmation to another B.php, normally this would be done with a AJAX call that will receive something in return.
2. Second B.php that receives the confirmation of the first A.php, does the UPDATES and returns something to tell the first A.php all the query went OK. If something goes wrong it could return a error code, or a error message detailing the error.
3. A.php shows the return of B.php to the user.

UPDATED CODE:

$.post("updatedatetime.php", $("#updateForm").serialize() ,function(data){
    alert(data);
}); 

The function(data) at the end is a callback function, that means that it will be executed once updatedatetime.php ends its execution. The variable data it receives is the return of updatedatetime.php (what you echo in that php)

To check if your AJAX is executing properly, if the variables have values, the return, etc. I would recommend to use Firebug, in its console it will display all this info.