Jquery Onchange事件未被触发

I have an onChange event, but upon change it is not being triggered. I have verified I am calling the fields correctly.

    $("#SRIEquipmentDDL").change(function() {
    if ($(this).val() == "3") {
        $("#SRILift").show();
    } else {
        $("#SRILift").hide();
    }
});

<div id="SRIEquipment">
            <div class="TextField">Equipment:</div>
            <div class="InputField">
                <select name="SRIEquipmentDDL" id="SRIEquipmentDDL" class="DropDownField">
                    <option value="0" <?php if ($_POST['SRIEquipmentDDL'] == "0") {echo "selected='selected'";} ?> >Select Chair Type</option>
                    <option value="1" <?php if ($_POST['SRIEquipmentDDL'] == "1") {echo "selected='selected'";} ?> >Manual Wheelchair</option>
                    <option value="2" <?php if ($_POST['SRIEquipmentDDL'] == "2") {echo "selected='selected'";} ?>>Power Wheelchair</option>
                    <option value="3" <?php if ($_POST['SRIEquipmentDDL'] == "3") {echo "selected='selected'";} ?>>Lift Chair</option>
                    <option value="4" <?php if ($_POST['SRIEquipmentDDL'] == "4") {echo "selected='selected'";} ?>>Scooter</option>
                    <option value="5" <?php if ($_POST['SRIEquipmentDDL'] == "5") {echo "selected='selected'";} ?>>Lifts</option>
                    <option value="6" <?php if ($_POST['SRIEquipmentDDL'] == "6") {echo "selected='selected'";} ?>>CPM</option>
                    <option value="8" <?php if ($_POST['SRIEquipmentDDL'] == "7") {echo "selected='selected'";} ?>>Walker</option>                          
                    <option value="9" <?php if ($_POST['SRIEquipmentDDL'] == "8") {echo "selected='selected'";} ?>>Other</option>
                </select>
            </div>
        </div>
        <div id="SRILift">
            <div class="TextField">Lift Type:</div>
            <div class="InputField">
                <select name="SRILiftTypeDDL" id="SRILiftTypeDDL" class="DropDownField">
                    <option value="0" <?php if ($_POST['SRILiftTypeDDL'] == "0") {echo "selected='selected'";} ?> >Select Lift Type</option>
                    <option value="1" <?php if ($_POST['SRILiftTypeDDL'] == "1") {echo "selected='selected'";} ?> >Stair Lift</option>
                    <option value="2" <?php if ($_POST['SRILiftTypeDDL'] == "2") {echo "selected='selected'";} ?>>Porch Lift</option>
                    <option value="3" <?php if ($_POST['SRILiftTypeDDL'] == "3") {echo "selected='selected'";} ?>>Outside Vehicle Lift</option>
                    <option value="4" <?php if ($_POST['SRILiftTypeDDL'] == "4") {echo "selected='selected'";} ?>>Inside Vehicle Lift</option>
                    <option value="5" <?php if ($_POST['SRILiftTypeDDL'] == "5") {echo "selected='selected'";} ?>>Ceiling Lift</option>                     
                    <option value="6" <?php if ($_POST['SRILiftTypeDDL'] == "6") {echo "selected='selected'";} ?>>Other</option>
                </select>
            </div>
        </div>

Try something like this:

 $('#yourSelectId').change(function() {
    var selectedVal = $('#yourSelectId option:selected').attr('value');
});

make sure you code is inside a ready function - http://api.jquery.com/ready/ or it is after the HTML that create the select

Can you try the the jquery bind() method?? If it doesn't work try to check the value inside your select ...may be there are INTEGERS try then change your condition to :

if ($(this).val() == 3) {

The problem you're facing is that often select boxes will not fire the change event while they are focused.

Since you are using JQuery, the solution is to use .click() in conjunction with .blur() in order to trigger the onchange event.

I found this Fiddle which demonstrates what you'll want to do:

http://jsfiddle.net/acrashik/wLWMc/

Try using live in your code

 $("#SRIEquipmentDDL").on('change',function() {
            if ($(this).val() == "3") {
                $("#SRILift").show();
            } else {
                $("#SRILift").hide();
            }
        });