IE 11 / Firefox中的FireEvent

Question

I have this situation of migration from IE 9 to 11 with added support for Firefox and one of my collegue has replaced

form.fireEvent("onsubmit");

with the following block

var event; // The custom event that will be created
if (document.createEvent) {
  event = document.createEvent("HTMLEvents");
  event.initEvent("submit", true, true);
  form.dispatchEvent(event);
} else {
  event = document.createEventObject();
  event.eventType = "submit";
  form.fireEvent("submit");
}

form.submit();

I couldn't understand what it means. Also is the above block correct?

Answer 1

1. if (document.createEvent){}

   Checking if this supported, since many method use to create custom event is depreciated

2. event = document.createEvent("HTMLEvents");

   if above is true then create Event object

   HTMLEvents is the type of event to be created. Check Here for more

3. event.initEvent("submit", true, true);

   Defining the event name.Here the event name is "submit".

   Normal syntax is event.initEvent(type, bubbles, cancelable);

4. form.dispatchEvent(event) ;

   dispatchEvent is the last step of the create-init-dispatch process, which is used for dispatching events into the implementation's event model. More about dispatchEvent

5. event = document.createEventObject();

This is to handle Internet Explorer. It generates an event object.

6. event.eventType = "submit";

   It will create an event of type "submit"

7. form.fireEvent("submit");

   This will fire the event on form

Hope this will be helpful to you.