当 readonly 为 true 时触发 TextBox 的 onchange 事件

Question

I am trying to have some functionality on change of a textbox which is readonly. But when I am trying to update the textbox using javascript, the change event is not firing for the textbox.

<script type="text/javascript">
        $(document).ready(function () {
            $('input[id$=_txtTest]').bind("change", function () {
                alert("test");
            });
                        });
        function ChangeText() {
            $('input[id$=_txtTest]').val('hello');
         }
    </script>

I am calling ChangeText method on click of a button. But it is not firing the textchange event for the textbox.

Can anybody tell me what is wrong here?

Answer 1

Well you have to do this way: http://jsfiddle.net/kmvSV/1/

 $(document).ready(function () {
   $('input[id$=_txtTest]').bind("change", function () {
     alert($(this).val());
   });
   $('button').bind("click", function () {
     $('input[id$=_txtTest]').val('hello').trigger('change');
   });
 });

Answer 2

The change event is triggered by real user events only not javascript actions.

You may trigger the change event, like so:

$('input[id$=_txtTest]').val('hello').change();

Answer 3

you can do like this

function setValueOfTextBox()
{
    var myElement = document.getElementById("textboxid");
    myElement.value = "hello";
    //following code fire change event for you text box
    if (myElement.onchange) 
         myElement.onchange();
}

Answer 4

I believe that for some security reason, the events are not fired. But you can achieve this by triggering the specific event on that element. Eg $('input[id$=_txtTest]').trigger('change');

I hope this helps someone.

Answer 5

onkeypress event or one of the several other events :

Since the read-only field doesn't really change; the onChange event doesn't trigger on it. However; there are several other events that you can listen to.

Here's a short demo:

 input { font-size: 16px; line-height: 30px; padding: 3px; border: 2px darkblue solid; }

 <script> function sayHi(evt) { alert('Are you tyring to edit a read-only? Click OK for details.') alert(JSON.stringify({ keyCode: evt.keyCode, charCode: evt.charCode, altKey:evt.altKey, ctrlKey: evt.ctrlKey, shiftKey: evt.shiftKey }), null, 2); } </script> <input onkeypress="sayHi(event);" readonly placeholder="A readonly field..." />