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#4071 closed bug (wontfix)

Opened February 06, 2009 07:14AM UTC

Closed October 27, 2012 08:21PM UTC

Last modified August 14, 2013 04:22AM UTC

Datepicker and ASP.Net validators. Error: 'length' is null or not an object

Reported by: scanbix Owned by:
Priority: major Milestone: 1.11.0
Component: ui.datepicker Version: 1.6rc6
Keywords: 'length' is null or not an object Cc:
Blocked by: Blocking:

I use ASP.NET 1.1 SP1 for my web page. And for date field I have native ASP.NET 1.1 validation.

In general datepicker works. But when I select date, then I get folowing error.

With firefox 3, same page works flawlesly, no conflicts with ASP.NET validation.


Webpage Script Errors

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; InfoPath.2; .NET CLR 1.1.4322; FDM)

Timestamp: Fri, 6 Feb 2009 07:06:39 UTC

Message: 'length' is null or not an object

Line: 139

Char: 17

Code: 0

URI: http://localhost/aspnet_client/system_web/1_1_4322/WebUIValidation.js

Attachments (0)
Change History (14)

Changed March 08, 2009 02:41PM UTC by rdworth comment:1

milestone: 1.71.8

Changed March 26, 2009 01:48AM UTC by ajacksified comment:2

To narrow it down a bit: it seems that it only happens when validation controls are attached to the box, in IE6 and 7. I've noticed this as well in .NET 3.5.

Changed April 19, 2009 11:16PM UTC by cblaze22 comment:3

I second this bug. This is a big problem with the compare validator validator for date.


Birthdate</label><br />

<asp:TextBox runat="server" ID="tbBirthdate" MaxLength="10" CssClass="text datePicker" />

<asp:CompareValidator runat="server" ID="rfvBirthdate" ControlToValidate="tbBirthdate"

ErrorMessage="Significant Other Birthdate" Display="None" ValidationGroup="vgPersons"

Type="Date" Operator="DataTypeCheck" />

Changed April 28, 2009 04:52PM UTC by BeSt comment:4

Hi, I found three main workarounds searching on Google:

1 - add an empty onSelect event to the datepicker

2 - modify DatePicker script source for IE as in

3 - disable validator client validation

I successfully use first solution because I don't want to edit source code and I want client validation enabled.

Sorry for my poor english...(italian version of this workaround:

Changed July 21, 2009 05:40AM UTC by kbwood comment:5

resolution: → wontfix
status: newclosed

This appears to be a problem with either the jQuery trigger function or the ASP validation code, rather than the datepicker itself. The datepicker is merely notifying a change in value by triggering the 'change' event on the input field. When this eventually reaches the ASP code the list of validators for the targetted control is empty - resulting in the error.

Changed December 30, 2009 10:57PM UTC by rdworth comment:6

resolution: wontfix
status: closedreopened

Changed December 30, 2009 11:02PM UTC by rdworth comment:7

Though not clear whether the true source of the problem is in Internet Explorer or in the ASP.Net Validator code, Internet Explorer is getting event.srcElement as the A that gets clicked on to select a date, rather than the original INPUT element.

The fix is to use createEventObject and fireEvent in Internet explorer, rather than .change(), supplying the INPUT element as the target property of the event object. For more, see

Changed December 31, 2009 01:27AM UTC by rdworth comment:8

summary: 'length' is null or not an objectDatepicker and ASP.Net validators. Error: 'length' is null or not an object

Created visual test page:

The workaround is to use .fireEvent('onchange') instead of .change()

onSelect: function() {
  this.fireEvent && this.fireEvent('onchange') || $(this).change();

Changed May 25, 2010 01:58PM UTC by ben.mcintyre comment:9

(Copy of stackoverflow post)

This is an endemic problem with jQuery datepickers and ASP validation controls.

The wrong element cross-triggers an ASP NET javascript validation routine, and then the M$ code throws an error because the triggering element in the routine is undefined.

I solved this one differently from anyone else I have seen - by deciding that M$ should have written their code more robustly, and hence redeclaring some of the M$ validator code to cope with the undefined element. Everything else I have seen is essentially a workaround on the jQuery side, and cuts possible functionality out (eg. using the click event instead of change).

The bit that fails is

for (i = 0; i < vals.length; i++) {

ValidatorValidate(vals[i], null, event);


which throws an error when it tries to get a length for the undefined 'vals'.

I just added

if (vals) {

for (i = 0; i < vals.length; i++) {

ValidatorValidate(vals[i], null, event);



and she's good to go. Final code, which redeclares the entire offending function, is below. I put it as a script include at the bottom of my master page or page.

Yes, this does break upwards compatibility if M$ decide to change their validator code in the future. But one would hope they'll fix it and then we can get rid of this patch altogether.

// Fix issue with datepicker and ASPNET validators: redeclare MS validator code with fix

function ValidatorOnChange(event) {

if (!event) {

event = window.event;


Page_InvalidControlToBeFocused = null;

var targetedControl;

if ((typeof (event.srcElement) != "undefined") && (event.srcElement != null)) {

targetedControl = event.srcElement;


else {

targetedControl =;


var vals;

if (typeof (targetedControl.Validators) != "undefined") {

vals = targetedControl.Validators;


else {

if (targetedControl.tagName.toLowerCase() == "label") {

targetedControl = document.getElementById(targetedControl.htmlFor);

vals = targetedControl.Validators;



var i;

if (vals) {

for (i = 0; i < vals.length; i++) {

ValidatorValidate(vals[i], null, event);





Changed May 25, 2012 03:01AM UTC by scottgonzalez comment:10

Replying to [comment:8 rdworth]:

The workaround is to use .fireEvent('onchange') instead of .change()

@rdworth That sounds bad. We shouldn't be working at that level in UI. Are you sure you really want this ticket open?

Changed October 11, 2012 02:43PM UTC by scottgonzalez comment:11


Changed October 27, 2012 08:19PM UTC by mikesherov comment:12

status: reopenedopen

Changed October 27, 2012 08:21PM UTC by mikesherov comment:13

resolution: → wontfix
status: openclosed

I agree with scott that this is not a jQuery UI bug here. If anyone feels strongly, please feel free to reopen.

Changed August 14, 2013 04:22AM UTC by janicelagundi comment:14

Try to add an empty onSelect handler to fix the issue : onSelect: function() {}

For more info :