Trigger a keypress/keydown/keyup event in JS/jQuery?

What is the best way to simulate a user entering text in a text input box in JS and/or jQuery?

I don't want to actually put text in the input box, I just want to trigger all the event handlers that would normally get triggered by a user typing info into a input box. This means focus, keydown, keypress, keyup, and blur. I think.

So how would one accomplish this?

You can trigger any of the events with a direct call to them, like this:

$(function() {
    $('item').keydown();
    $('item').keypress();
    $('item').keyup();
    $('item').blur();
});

Does that do what you're trying to do?

You should probably also trigger .focus() and potentially .change()

If you want to trigger the key-events with specific keys, you can do so like this:

$(function() {
    var e = $.Event('keypress');
    e.which = 65; // Character 'A'
    $('item').trigger(e);
});

There is some interesting discussion of the keypress events here: jQuery Event Keypress: Which key was pressed?, specifically regarding cross-browser compatability with the .which property.

You could dispatching events like

el.dispatchEvent(new Event('focus'));
el.dispatchEvent(new KeyboardEvent('keypress',{'key':'a'}));

To trigger an enter keypress, I had to modify @ebynum response, specifically, using the keyCode property.

e = $.Event('keyup');
e.keyCode= 13; // enter
$('input').trigger(e);

Here's a vanilla js example to trigger any event:

function triggerEvent(el, type){
if ('createEvent' in document) {
        // modern browsers, IE9+
        var e = document.createEvent('HTMLEvents');
        e.initEvent(type, false, true);
        el.dispatchEvent(e);
    } else {
        // IE 8
        var e = document.createEventObject();
        e.eventType = type;
        el.fireEvent('on'+e.eventType, e);
    }
}

You can achieve this with: EventTarget.dispatchEvent(event) and by passing in a new KeyboardEvent as the event.

For example: element.dispatchEvent(new KeyboardEvent('keypress', {'key': 'a'}))

Working example:

// get the element in question
const input = document.getElementsByTagName("input")[0];

// focus on the input element
input.focus();

// add event listeners to the input element
input.addEventListener('keypress', (event) => {
  console.log("You have pressed key: ", event.key);
});

input.addEventListener('keydown', (event) => {
  console.log(`key: ${event.key} has been pressed down`);
});

input.addEventListener('keyup', (event) => {
  console.log(`key: ${event.key} has been released`);
});

// dispatch keyboard events
input.dispatchEvent(new KeyboardEvent('keypress',  {'key':'h'}));
input.dispatchEvent(new KeyboardEvent('keydown',  {'key':'e'}));
input.dispatchEvent(new KeyboardEvent('keyup', {'key':'y'}));

<input type="text" placeholder="foo" />

MDN dispatchEvent

MDN KeyboardEvent

Trigger a keypress/keydown/keyup event in JS/jQuery?

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