When an Event is triggered by a user in IE, it is set to the window.event object. The only way to see what triggered the event is by accessing the window.
This is an endemic problem with jQuery datepickers and ASP validation controls. As you are saying, 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 = event.target;
}
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);
}
}
ValidatorUpdateIsValid();
}