当PHP脚本更改了Select（组合框）时，引发onChange事件

Question

Here is the code for combobox

<select name="cmbdegree" id="cmbdegree" class="styledselectevents">
    <option value="0">Select Degree</option>
    <?php                       
        $newque="SELECT * FROM degrees";                        
        $qu=mysqli_query($conn, $newque);                       
        while($rs=mysqli_fetch_array($qu))                      
        {                   
    ?>
        <option value="<?=$rs['id']?>" <?php if($rs['id'] === $rsSemDegID) { echo 'Selected'; } ?>><?=$rs['Title']?></option>
    <?PHP } ?>
</select>

Now I have a JQuery to run on the change

$(document).on('change', '#cmbdegree', function() {
    var val = $(this).val();
    $.ajax({
        url: 'gettotalsemesters.php',
        data: {
            cmbdegree: val,
            seldeg: $rsSemDegID
        },
        type: 'GET',
        dataType: 'html',
        success: function(result) {
            $('#SemsterNum').html();
            $('#SemsterNum').html(result);
        },
        error: function() {
            alert('Error occured');
        }
    });
});

It works when user changes it .. but I want it to raise the change event when the selection has been done by PHP script.

Answer 1

Try this, Trigger change event after page loaded

    $(document).on('change', '#cmbdegree', function() {
        var val = $(this).val();
        $.ajax({
            url: 'gettotalsemesters.php',
            data: {
                cmbdegree: val,
                seldeg: $rsSemDegID
            },
            type: 'GET',
            dataType: 'html',
            success: function(result) {
                $('#SemsterNum').html();
                $('#SemsterNum').html(result);
            },
            error: function() {
                alert('Error occured');
            }
        });
    });

$('#cmbdegree').trigger("change"); //<--------trigger event