Change `<select>`'s option and trigger events with JavaScript

javascript

event-handling

browser-compatibility

javascript-events

byAnton Shumikhin·Dec 31, 2024

Here's your quick code snippet to select an option in a <select> dropdown and subsequently fire off its change event:

// Capture the dropdown like a Pokémon master
const select = document.querySelector('#yourSelect');

// Set the desired option (Gotta catch 'em all!)
select.value = 'desiredOptionValue'; 

// Unleash the Kraken, err... trigger the change event!
select.dispatchEvent(new Event('change'));

This comes in handy when you need to swiftly tweak the selected option and ignite the change event listeners linked to your dropdown.

Meeting Cross-browser Consistency

Composing a symphony of browser compatibility? You need the right notes! The Event constructor is the preferred instrument for most modern browsers. However, it sounds a bit out of tune on Internet Explorer. For IE, direct your orchestra towards a method like createEventObject or use a polyfill to mimic the Event constructor's functionality.

// IE-proof trigger change event
if (typeof select.fireEvent !== 'undefined') {
  var event = document.createEventObject();
  event.eventType = 'change';
  select.fireEvent('onchange', event);
} else {
  select.dispatchEvent(new Event('change'));
}

Always kick off a browser compatibility concert tour to ensure consistent performances of your event triggering.

Jazzing up with Advanced Event Handling

For those wanting to compose more complex event symphonies, getting the right notes on the event score is crucial. Set event properties such as its type, bubbling, and cancelable to orchestrate the behaviour you want in your event:

let event = new Event('change', {
  bubbles: true, 
  cancelable: true
});
select.dispatchEvent(event);

For Firefox, you can play a different tune using createEvent and initEvent for tailor-made customized events:

let event = document.createEvent('HTMLEvents');
event.initEvent('change', true, false);
select.dispatchEvent(event);

Selecting Options Dynamically

Need some improv within your performance? Create dynamic changes to your <select> options based on the live audience's requirements or the latest Billboard charts:

// Changing selection based on crowd's favorite
select.selectedIndex = 2;

// Adding a new hit song to the playlist
let newOption = new Option("Hot New Track", "newOptionValue");
select.add(newOption);

// "Sorry, we don't play 'Despacito' anymore"
select.remove(1);

Don't forget the encore: trigger the change event to keep your application's stage and audience in sync!

Handling the 'What Ifs?': Edge Cases and Potential Issues

While you're taking your <select> elements on a world tour, anticipate a few tour bumps that may affect the concert experience:

Multiple Listeners: There could be multiple band managers listening to the same change event. Don't let your programmatic event trigger ignite a celebrity feud.
Audience Feedback: Flashing lights or stage effects to accompany your song selection can enrich the concert experience, especially if it's programmed.
onchange Attribute: Simplify event setup using the onchange attribute directly in HTML when it's practical, but remember, it can turn into a backstage mess in larger events.

Staying on Beat: Best Practices and Additional Insights

Let's wrap up the concert with some final thoughts:

Band Managers (Listeners): Use addEventListener to avoid backstage drama (inline JavaScript) and maintain a professional gig environment.
Impersonate the Artist: Emulate user actions when triggering changes programmatically to ensure fans (functions) maintain expected functionality.
Rehearsals: Always do a sound check! Or, review practical examples on platforms like JSFiddle to brush up your performance.