Trigger form submission with javascript

Question

I have a form that I would like to submit via JavaScript. Obviously this can be achieved by:

document.getElementById("myForm").submit();

The issue is that I have a listener on the submit event that looks like this:

document.getElementById("myForm").addEventListener("submit", function(event) {
    event.preventDefault();
    // Other work
});

This event handler is not triggered when I call .submit(). From MDN:

The form's onsubmit event handler (for example, onsubmit="return false;") will not be triggered when invoking this method from Gecko-based applications. In general, it is not guaranteed to be invoked by HTML user agents.

So, given this restraint, how can I submit the form in a way that ensures the event handler is invoked?

Answer 1

You need create a submit event, then dispatch it.

(function () {
              if ( typeof window.CustomEvent === "function" ) return false;

              function CustomEvent ( event, params ) {
                params = params || { bubbles: true, cancelable: true, detail: undefined };
                var evt = document.createEvent('submit');
                evt.initCustomEvent( event, params.bubbles, params.cancelable, params.detail );
                return evt;
               }

              CustomEvent.prototype = window.Event.prototype;

              window.CustomEvent = CustomEvent;

})();
var evt = new CustomEvent("submit", {"bubbles":true, "cancelable": true});
document.getElementById("myForm").addEventListener("submit",function(event) {
                event.preventDefault();
                alert('submit');
});

Then when you want submit this function you need to call:

!document.getElementById("myForm").dispatchEvent(evt);

For more event info see dispatchEvent.