How can I trigger an onchange event manually? [duplicate]
I'm setting a date-time textfield value via a calendar widget. Obviously, the calendar widget does something like this :
document.getElementById('datetimetext').value = date_value;
What I want is:
On changing value in the date-time textfield I need to reset some other fields in the page. I've added aonchange
event listener to the datetimetext
field which is not getting triggered, because I guess onchange
gets triggered only when the element gets focus & its value is changed on losing focus.
Hence I'm looking for a way to manually trigger this onchange
event (which I guess should take care of checking the value difference in the text field).
Any ideas?
There's a couple of ways you can do this. If the onchange
listener is a function set via the element.onchange
property and you're not bothered about the event object or bubbling/propagation, the easiest method is to just call that function:
element.onchange();
If you need it to simulate the real event in full, or if you set the event via the HTML attribute or addEventListener
/attachEvent
, you need to do a bit of feature detection to correctly fire the event:
if ("createEvent" in document) {
var evt = document.createEvent("HTMLEvents");
evt.initEvent("change", false, true);
element.dispatchEvent(evt);
}
else
element.fireEvent("onchange");
MDN suggests that there's a much cleaner way of doing this in modern browsers:
// Assuming we're listening for e.g. a 'change' event on `element`
// Create a new 'change' event
var event = new Event('change');
// Dispatch it.
element.dispatchEvent(event);
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