Question

I am getting two sets of errors I can;t seem to figure out. One is a error in my javascript in my error console stating:

Syntax Error: missing ; before statement:
Notice: undefined variable courseDatas in ..... line 28

The other error I am getting is a mysqli/php error which states:

Warning: array_push() expects parameter 1 to be array, ... on line 247

How can both these errors be removed?

Javascript:

<script type="text/javascript">
    $(document).ready( function(){
        var coursedatas = <?php echo json_encode($courseDatas); ?>; //error here
        $('#coursesDrop').change(function()
        {
            var courseId = $(this).val(),
            coursedata;
            for (var i = 0, l = coursedatas.length; i < l; i++)
            {
                if (coursedatas[i].courseId = courseId) { coursedata = coursedatas[i]; }
            }
            var index = $('#newDuration option[value="' + courseData.Duration + '"]').index('#newDuration option');
            $('#newDuration')[0].selectedIndex = index;
        });
    });
</script>

…..

PHP:

$coursequery = "
    SELECT CourseId, CourseNo, CourseName, Duration
    FROM Course
    ORDER BY CourseNo
";

$courseqrystmt=$mysqli->prepare($coursequery);
// You only need to call bind_param once

$courseqrystmt->execute();   
$courseqrystmt->bind_result($dbCourseId,$dbCourseNo,$dbCourseName,$dbDuration);
$courseqrystmt->store_result();
$coursenum = $courseqrystmt->num_rows();     
$courseHTML = '';
$courseHTML = '<select name="courses" id="coursesDrop">'.PHP_EOL;
$courseHTML .= '<option value="">Please Select</option>'.PHP_EOL;           

while ( $courseqrystmt->fetch() ) {
    $courseHTML .= sprintf("<option value='%s'>%s - %s</option>", $dbCourseId,$dbCourseNo,$dbCourseName) . PHP_EOL;  
    $courseData = array();
    $courseData["CourseId"] = $dbCourseId;
    $courseData["CourseNo"] = $dbCourseNo;
    $courseData["CourseName"] = $dbCourseName;
    $courseData["Duration"] = $dbDuration;

    array_push($courseDatas, $courseData); //error here
}    
$courseHTML .= '</select>';

Answer 1

The $courseDatas variable needs to be defined outside of your while loop as an array.

EDITED – HERE IS WHAT YOUR SCRIPT NEEDS TO LOOK LIKE:

$coursequery = "SELECT CourseId, CourseNo, CourseName, Duration FROM Course
ORDER BY CourseNo";
$courseqrystmt=$mysqli->prepare($coursequery);
// You only need to call bind_param once
$courseqrystmt->execute();
$courseqrystmt->bind_result($dbCourseId,$dbCourseNo,$dbCourseName,$dbDuration);
$courseqrystmt->store_result();
$coursenum = $courseqrystmt->num_rows();
$courseHTML = '';
$courseHTML = '<select name="courses" id="coursesDrop">'.PHP_EOL;
$courseHTML .= '<option value="">Please Select</option>'.PHP_EOL;
$courseDatas = array();
while ( $courseqrystmt->fetch() ) {
    $courseHTML .= sprintf("<option value='%s'>%s - %s</option>",$dbCourseId,$dbCourseNo,$dbCourseName) . PHP_EOL;
    $courseData = array();
    $courseData["CourseId"] = $dbCourseId;
    $courseData["CourseNo"] = $dbCourseNo;
    $courseData["CourseName"] = $dbCourseName;
    $courseData["Duration"] = $dbDuration;
    array_push($courseDatas, $courseData); //error here
}
$courseHTML .= '</select>';

<script type="text/javascript">
    $(document).ready( function(){
        var coursedatas = '<?=json_encode($courseDatas);?>';
        //now we have established some data for the $courseDatas array!
        $('#coursesDrop').change(function()
        {
            var courseId = $(this).val(), coursedata;
            for (var i = 0, l = coursedatas.length; i < l; i++)
            {
                if (coursedatas[i].courseId = courseId) { coursedata = coursedatas[i]; }
            }
            var index = $('#newDuration option[value="' + courseData.Duration + '"]').index('#newDuration option');
            $('#newDuration')[0].selectedIndex = index;
        });
    });
</script>